Author's Note: There was a total solar eclipse visible from Northern Italy in February of 1961, followed by an eclipse of the moon that July. Yes, I did look that up, because I'm a nerd. Also, if you read this on my AO3 instead of here, there are pictures now. I won't promise they're good pictures but they exist.

The first thing Giulia noticed about the mushroom-shaped rock formation the Paguro family used as a dining table was that there were no chairs... but then, they didn't need chairs. As she'd already observed, when sea monsters stopped moving, they tended to just hang in the water without floating up or sinking down, so they didn't need anything to support them as they gathered around to eat. Daniela set out the large shells and hollowed-out stones they used as tableware, and Luca smiled to himself thinking of the Christmas present he'd brought back from Genova for her.

"Here," he said, reaching for a mussel shell. "Giulia, I'll show you how to open them."

"So what have you kids been up to all afternoon?" Daniela asked, distributing the dark green kelp dumplings.

"Mostly showing Giulia around," Luca replied. "Tomorrow we're gonna decorate a Christmas sponge for us." He looked around the room for a place to put it, and spied a possibility. "How about in the alcove there? We'll just have to move Dad's crab feed." The alcove was currently home to a sizable basket of it, which one of the crabs was trying to climb into without success. Luca bit into a dumpling and chewed thoughtfully. "Dad? Do you know who Oannes is?"

"Who?" asked Lorenzo, working on a recalcitrant mussel.

"Oannes," Luca repeated. "The genie called us Children of Oannes."

"I've never heard of him," Lorenzo said.

"Do you know anybody who might?" Luca asked.

"Maybe Ugo," Lorenzo suggested. "He knows all kinds of strange things. He once told me he found an entire locomotive on the bottom of the ocean, just sitting there. It wasn't even just off the coast, it was a kilometre down, where the sunlight stops."

"I... guess," said Luca, unhappy with the idea. Uncle Ugo had not made a good first impression. Part of that was probably the circumstances... but a significant part was definitely Ugo Paguro himself.

"Hey, speaking of questions," Alberto said, stuffing another dumpling into his mouth. "Luca, last night you were saying how the big sky fish – the Moon – changes shape because different parts of it are lit up. So why does it sometimes turn red?"

"Red?" asked Luca, puzzled. "You mean how it's big and orange when it's still low?"

"No, I mean really dark red," Alberto insisted. "I saw it a year or so ago. My Dad had been away all day so I stayed up waiting for him, and the moon went dark and then turned all red. I watched it every night after that for ages, but it never did it again."

Luca gave him a sideways look. He knew that Alberto sometimes said things that weren't true, in the attempt to make himself sound cooler. "Uh..." he began.

"Oh! I know why!" said Giulia. Her mouth was full of mussel, and she had to finish swallowing before she could speak properly. "That's an eclipse! I saw the same one. Papà let me get up in the middle of the night to watch it. It's when the Earth is right in between the Sun and the Moon, so it casts a shadow on the Moon."

"Shadows aren't red, though," Alberto pointed out.

"But when the Moon is in the Earth's shadow, it gets some of the light that comes around the edges of the planet," Giulia explained. "So the red colour is all the sunrises and sunsets in the world at the same time."

"Really?" Luca asked, his eyes huge.

"Yeah! We covered this in astronomy class that year, after the solar eclipse in February," Giulia said. "Did you see that one, too, Alberto? It was cloudy in Genova, so all we saw was it getting really dark."

"No..." said Alberto uncertainly. "At least, I don't remember it."

"If you'd seen it, you'd remember," Giulia assured him. "A solar eclipse is when the Moon goes between the Earth and the Sun, and covers the Sun perfectly. It's the only time when we can see the corona, which is all this wispy stuff around the Sun. I'll find you a picture," she promised.

"Is there gonna be another one?" asked Luca, fascinated. At the time it had happened he hadn't even known something like that was possible. He'd been only barely aware that the Sun and Moon even existed, having only seen shadows of them through a dozen metres of water.

"I don't know. They're very rare," said Giulia. "Lunar eclipses like Alberto saw are more common."

Luca was crushed. To think that something so amazing had been happening right over his head, and he'd totally missed it.

"You wouldn't have been able to see it anyway," Giulia reminded him gently. "Cloudy, remember?"

"Yeah," he said.

Daniela shook her head. "I thought all that weather made the land unpredictable enough!" she said. "Now apparently the sun and moon just go dark or change colour sometimes? That sounds terrifying."

"You get used to it," Alberto assured her.

For dessert they had bubble algae, with their smooth glassy surfaces and sweet, jellylike innards. Eaten raw they had an edge to them like a sour apple, and burst in the mouth like grapes. As promised, Luca got first pick as a reward for catching the most fry. His hand hovered indecisively over the giant clam shell his mother had filled with the delicacies.

"I kind of want to pick the biggest one," he said, "but Giulia's a guest..."

"Go ahead and take it," she urged him. "It's not like I'm never coming back, right?"

"No... it's not, is it?" Luca realized. He'd been thinking like this was a once and never again thing, but as they'd told Giulia's parents, they had no reason to believe that. She would be a sea monster for the rest of her life, and they could have as many dinners and sleepovers as they wanted. So he took the biggest bubble alga – but also took the smallest for his second one, so that it wouldn't be too unfair.

After dinner, the boys got the extra mattresses – made of strips of sponge woven together with seaweed stems – out of storage, while Giulia volunteered to help with the dishes. Daniela showed her how to turn them upside-down so they would trap the hot vent water, then scour them out with a handful of sand.

"Do you have to cook stuff in upside-down dishes, too?" Giulia asked. That sounded awkward.

"No, we do most of our cooking in baskets," Daniela explained. "If the lid's on, the hot water can pass through but the food can't float out. Your father's been trying to teach me surface-type cooking and I just can't get the hang of it. He says the water for pasta needs to be salty enough to make it taste like the sea, but the sea doesn't taste like anything. It'd be like me telling him something should smell like air."

Giulia giggled, and swirled some water in her mouth to see if she could still taste the salt. She could, but only if she specifically tried to.

"So how does the food compare?" asked Grandma, who was back to working on her knitting.

"I was surprised," Giulia admitted. "I kind of thought it was going to be bland because I know you don't have cheeses or some of the spices down here, but it was really good. The dumplings tasted almost like bacon."

"That's the kelp, it's very savoury," Daniela said. "I was surprised by human food, too. When Mom told me pasta is just ground-up seeds and bird's eggs, I thought she was pulling my tail. But you can put all those sauces and powders on it that would just wash away down here. It's a very different approach to cooking."

"Maybe while Dad teaches you land cooking, you can teach me some sea cooking," Giulia suggested.

"That's a great idea," said Grandma. "We need to pass these family recipes on to somebody, and Luca's hopeless at cooking."

"He gets to daydreaming," Daniela said, "and while he's distracted everything just boils to bits."

"That sounds like Luca," Giulia agreed with a smile. "We'll have to do that when I come home again for the summer." She was going to learn an awful lot, she thought – and realized this must be how Luca felt about going to school, like a whole new world had suddenly opened up to him.

Once the clean-up was done, the boys took Giulia up to the tower roof, where they lay down in the seaweed and watched the plankton again while playing a game of Would-You-Rather. The stormy weather on the surface made the bioluminescence much brighter and more active tonight, with bright stripes of it sliding by on each wave. At one point a small shark swam over, silhouetted against the swirling blue glow.

"Sleeping under the fish!" Giulia exclaimed suddenly. "That's why you said that – because when you're outdoors down here, sometimes fish swim over. Is that why you thought the stars were fish?" she asked.

"No, Alberto told me the stars were anchovies," said Luca.

"And my Dad told me," Alberto said. "I just made up the bit about touching the Moon. Anyway, it's my turn, isn't it?" He thought for a moment. "Okay, here: would you rather fight one horse-sized seahorse, or a hundred seahorse-sized horses?"

"The small ones," Luca replied immediately.

"But there's a hundred of them," Alberto reminded him.

"Yeah, but they can't climb," Luca pointed out. "They don't have hands. So all I'd have to do is stand on a chair."

Giulia laughed aloud at the mental image of Luca standing on a kitchen chair while tiny, furious horses swarmed around its legs. "If I had a horse-sized seahorse," she said, "I wouldn't try to fight it. I'd want to ride it."

"They're really slow," said Alberto.

"And they swim with their dorsal fins," Luca added, yawning. "So if you were sitting on its back it wouldn't be able to go anywhere."

"Yeah, but it would look cool," Giulia said. She put her hands behind her head, pushing her fingers through the ribbon-like fins like she normally would through her hair, and thought about what she was going to ask. The clouds must have been clearing, she observed, because there was a bright patch behind the glowing algae that must have been the Moon, wavering as the water moved beneath it. "Okay, would you rather live on land forever but only be able to eat sea monster food, or live in the water but only be able to eat human food?"

"Oh, that's hard," Alberto complained. "I don't think humans could eat some of the stuff we do. You need sharper teeth. But if you take human food underwater..."

"It'll just fall apart," Giulia agreed. "Imagine trying to eat lasagna down here, with all the layers floating away!"

Alberto scratched behind his gills while he thought about it. "I'm gonna have to say live on land and eat ocean food," he said. "There's stuff up there I'd miss too much. What about you, Luca?"

Luca didn't answer. Giulia and Alberto turned to look at him,and found that he'd fallen asleep.

"Aw," said Alberto with a smile. "He did that on the Island once. Just fell asleep in the middle of a conversation. Woke up like three hours later and panicked because he was gonna be in trouble for not coming home."

"He did it in school, too," Giulia giggled. "We'd been up late studying for a geography test, and he stayed awake long enough to take it but when the teacher called on us to hand the papers in, he was face-down on his desk, fast asleep. He'd answered all the questions, but he did drool on it a little." She grinned. "You think we can get him inside without waking him up?"

"Nah, but his Dad probably can," said Alberto. He slid off the edge of the roof and swam down to get Lorenzo.

Luca did wake up a little as his father carried him to his room, but once he was settled on the seaweed-covered stone that served him as a bed, he just rolled over and curled up, clutching the end of his tail. Lorenzo gave his son a quick kiss on the forehead before turning to the two guests.

"Don't you two stay up all night and keep Grandma awake," he warned them.

"We won't, Signor Paguro," said Giulia, yawning herself. "We're pretty tired too." It had been a very strange, very exciting, and very tiring day.

Like cooking, beds underwater turned out to work a bit differently. Because sea monsters didn't tend to float or sink, lying down on top of something wasn't really possible. Instead, she quickly realized that the point of the sponge mattress, or of the thick layer of seaweed on Luca's shelf of stone, was to keep sleepers from waking themselves up by knocking a knee or elbow against the rocks in the middle of the night.

That was definitely good, but the arrangement did make it difficult for Giulia to nod off. She would shut her eyes and float there, only to wake with a start, feeling as if she were falling. That happened in bed sometimes, too, but now that she actually was in midair – or at least midwater – it was over and over again. In order to get comfortable, she had to wiggle down so she was touching the layer of sponge and get her fingers and toes into it so she wouldn't float away again.

It made her wonder what sleeping on land had been like for Luca the first few nights. Alberto had been doing it his whole life and probably didn't remember the first time, but Luca might've had some trouble adjusting to it. She would have to ask in the morning... along with a dozen other things she was wondering about.

By morning, the sky had cleared completely, and sunlight was shining down through the water through the windows of the Paguro house. Breakfast was something that at first looked like porridge to Giulia, until Luca's mother began serving it out – whereupon she realized it was actually little burst objects, like popcorn but with a jellyish texture. She couldn't figure out what they actually were until Daniela offered her some.

"Squid eggs, Giulia?" she asked pleasantly.

"Oh," said Giulia, suddenly less hungry than she'd been.

"You don't have to," said Luca, although his own mouth was full of them.

"No, I'll try them," Giulia decided. The boys certainly seemed to like them.

Daniela put a couple of them in a shell for her to taste. "I'm guessing you three have another busy day planned."

"Real busy," Alberto agreed cheerfully. "Lots to do."

"And after that it's you guys' turn to sleep over at my house," Giulia reminded them. She carefully put one of the squid eggs in her mouth, worried it would be rubbery like calamari sometimes was. Instead, it turned out to be soft like a hard-boiled hen's egg, and tasted almost like butter.

"What do you think?" Daniela asked.

"They're good," she said. "I'll have some more."

While Luca's mother filled Giulia's bowl, Grandma swam in to take her own place at the table.

"Morning, Mom," said Daniela. "They didn't keep you up, did they?"

"Not at all. They were silent as starfish, all three of them," Grandma said. She took the bowl of squid eggs out of Daniela's hands and helped herself.

"I had a dream," Alberto announced, "that it snowed on the Island, so instead of building another Vespa we turned the ramp over and slid down on that."

"Sledding!" said Luca. "The kids at school talked about trying it if the snow stayed long enough. We thought I might get too wet, though." He glanced at Giulia, remembering what her mother had said about there being things she wouldn't be able to do anymore. Sledding would probably be one of those.

"Don't gotta worry about that here," Alberto said. "Maybe it will snow."

Giulia chewed thoughtfully on another egg... Alberto's mention of a dream had reminded her of something. "I think I dreamed that I was sitting in class," she said, "and everybody was staring at me. Then I realized I was all wet and had turned into a sea monster, and then I woke up."

"I used to have dreams like that," said Luca. "When I was first hanging out with Alberto on the Island and it was still supposed to be a secret. I would have dreams where I got back in the water but I didn't Change, or only part of me did, and I couldn't go home because Mom and Dad would see. It never actually happened."

"That's why you need to get kids used to it when they're young!" snorted Grandma. "Trouble's parents had at least one good idea in their lives – you can do the Change from the day you're born, so you should let kids play with it so they know it's natural and they don't get all upset about it. There's no reason for them to be scared of their own bodies."

"There's such a thing as too young, Mom," said Daniela reproachfully.

"I used to think so, too," Grandma replied. "You don't remember the thing with the land seal, do you?"

"Land seal?" asked Luca.

"Yeah. Your Mom was about five or six. The neighbours had been telling her stories about humans putting our heads on the front of their ships to scare their enemies and it was giving her nightmares," Grandma explained, "so I thought I'd find her a little dress, take her into town for a treat, and show her it was okay. But this fellow had a great big land seal... what do you call those?" She looked at Giulia.

"A dog?" Giulia guessed.

"One of those." Grandma nodded. "I don't know if it didn't like us or if it was upset about something else, but it barked up a storm. Daniela dropped her gelato and burst into tears, and she refused to ever go back."

"Is that why you were scared of the surface?" Luca asked his mother.

"I had plenty of reasons to be worried about you two wandering around alone up there," Daniela huffed, embarrassed. "As Mom said, I don't even remember that."

That was when a shadow appeared in the doorway. Everybody looked up from their food as a familiar voice announced, "hello, Family!"

Luca's heart leaped into his throat and stayed there. He knew that voice, and the memory associated with it was not a good one.

"Ugo!" said Lorenzo Paguro, as his older brother floated into the room. "What brings you back to the shallows?"

"It is solstice season!" Uncle Ugo replied. He approached the table, the morning sunlight through the doorway outlining his organs starkly through his transparent skin. He must have just finished breakfast, because his stomach was busily squeezing its contents... or maybe he hadn't finished, because he was carrying a sack of something that seemed to be moving. "When I visited in the summer it made me think, it has been too long! Luca's almost grown and I barely know the boy. So I came to surprise you for the holiday. Very good. I like surprises."

Alberto leaned closer to Luca. "I thought you were exaggerating about the see-through part," he whispered.

"Nope," said Luca gloomily.

"It's definitely a surprise, Lorenzo said. "Thing is, I'm afraid we already have company..."

"So I see," Ugo agreed, smiling at the children with far too many sharp, glassy teeth. "These are your friends, Luca?"

"Yes, Uncle Ugo," said Luca. "This is Alberto."

"Hello," said Alberto warily.

"And this is Giulia."

"Ciao." She gave an awkward wave, her eyes still fixed on Ugo's moving digestive system. His intestines were mostly hidden by his trousers, but the tops of them could be seen, pumping their contents along.

"Nice to meet you," said Ugo, and held up his bag. "Would anyone like some treats?"

"Uh... treats?" asked Luca.

Ugo reached into the bag and pulled out something that must have been an animal because it was wiggling too much to be a plant. One end was a yellowish cone-shaped capsule, from which protruded a thin a thin pink creature that divided into several feathery tendrils at the other end.

"You don't have these up here," he said. "The Osedax worm lives only in the whale carcass, where it burrows into the bone to consume the marrow." He put the end of the thing in his mouth and sucked it down with a slurp, like a piece of spaghetti. "They are delicious. The mucus, yes. It melts in the mouth. Would you like to try?" He took out a second worm and offered it to Luca.

"No, thanks, Uncle Ugo," said Luca, edging away as if afraid the worm would attack him. "I already ate."

"We had a big breakfast," Alberto agreed.

Giulia raised a tentative hand. "I'll try it."

The boys stared at her.

"I'm a sea monster now. I want to do things sea monster do," she said firmly. She'd just eaten a squid egg and it had tasted good. How did she know this worm wouldn't be the same unless she tried it?

"I think this is more of just a thing Uncle Ugo does," Luca replied.

Ugo was very pleased. "Yes, good! I like your friend, Luca," he said, and held out the second worm to Giulia. "This is the female. The male is very small and lives inside her body. Dozens of them. The more there are, the more you taste pepper. Very nice."

She was already having second thoughts as she took it from his translucent hand. She could feel the thing's muscles tighten under her fingers, and Luca and Alberto were watching in the kind of transfixed horror usually reserved for sights like traffic accidents. But Giulia had already said she'd try it, and she wasn't going to back down now. She shut her eyes and put it in her mouth.

She nearly gagged. It wasn't the taste, it was the texture: the worm was surrounded by a layer of slime that made the experience something like having a bad cold and getting a mouthful of snot... if that snot were also moving. It was all she could do to force herself to swallow, then her first instinct was to find something to drink and wash it down, but sea monsters didn't drink from glasses and there was nothing. All she could do was mumble an apology as she snatched a squid egg off Alberto's plate and stuffed that in her mouth instead.

"Did you like it?" asked Uncle Ugo, tapping his fingertips together eagerly.

"Not really. It's too slimy for me." Giulia managed a weak smile.

"At least you tried," said Uncle Ugo, patting her head. "Well, then, more for me! Would you children like to see what I found in the Hellenic Trench last year? Very interesting. I saved it to show..." he rummaged in his bag of worms.

Giulia pushed herself away from the table. "Sorry, but I promised I'd check in with my parents right after breakfast."

"And we're going along, too," Luca agreed.

"Stuff might've shifted during the storm so she needs a guide who knows the area," Alberto said, cramming a final few squid eggs into his mouth.

"Right, Mom?" Luca looked at his mother for backup.

"Oh, I don't know," said Daniela, pretending to be doubtful. "You know what they say about waiting twenty minutes to get out of the water after eating..."

"That's a myth!" Alberto scoffed.

"And it'll take us at least that long to get back to shore anyway," Luca agreed.

Daniela smiled. "Go ahead... although Luca, I'd like to have a word before you go."

That sounded like trouble. "Yes, Mom," he said with a gulp.

Alberto and Giulia waited out front, while Daniela took Luca into a corner of the kitchen to talk to him. "Luca," she said gently, "I know you didn't meet Uncle Ugo under the nicest of circumstances, but he is family. He said he wants to get to know you. That means you're going to have to spend some time with him while he's here, okay?"

"But..." Luca pointed at the door.

"I know," she said. "But like she said last night, Giulia will be able to come back. You've got lots of time to show her the whole ocean. Uncle Ugo is here now. Do you understand?"

"Yes, Mom," he sighed.

"I promise you, he's not as bad as all that," Daniela assured him, smoothing his fins. "Now... look me in the eye." She waited for Luca to raise his head. "You know I love you, right?"

"I love you, too, Mom," said Luca.

She kissed his cheek. "Go have fun."

With a sigh of relief, Luca rejoined his friends out front. His grandmother had gone to float out there, too, and was currently cutting the last few stray bits of seaweed from her knitting with an obsidian knife. Satisfied with her work, she turned it right-side out and presented it to Giulia. "There you go, Small Fry," she said, holding out a seagrass version of Giulia's favourite beanie hat. "Try that on for size."

"Oh, thank you!" Giulia pulled it on, then rearranged it a little to keep it from pinching her fins, which unlike hair had a bit of sensation in them at the base. "There!"

"Looks good," said Alberto, giving her a thumbs-up. "Luca, what did your Mom want?"

"She said I have to hang out with Uncle Ugo a little while he's here," Luca explained. "I guess that's fair... and Dad did tell me I should ask him about Oannes." Although Luca was worried that anything Uncle Ugo would have to say about it would be stuff he ended up wishing he didn't know. He looked at Giulia. "I can't believe you really ate that worm. What did it taste like?"

"I didn't taste it," she admitted. "I just swallowed it because I knew if I tried to chew I would end up spitting it out. It was covered in goo." She made a face, then looked down at her torso. "You don't think I'm gonna go all see-through, do you?"

"I think you'd have to eat more than one," Luca decided.

"Good, because that would look really strange when I change back. Has your Uncle ever been up on land?"

"I doubt it – he lives in the Deep, and that's as far away from land as you can get," said Luca. "I like the hat, by the way... it makes you look more like human-you."

Giulia decided that was probably a compliment. "What do I look like?" she asked. "I sort of know, but... what colour are my eyes? Alberto's stay green, but Luca's get less red and more brown when he goes human."

"They're bright pink, kind of like Mom's," said Luca.

"Find a nice calm spot," Grandma told her, "and if you get the right angle, you can see your reflection in the surface from below, just like you can from above."

"I'll try that, thanks!" said Giulia. "See you later, Nonna Francesca." She waved, and the three kids swam off towards the shore.

The morning air was still very cold and there was frost on the rocks, but the wind and ocean were calm now, and the three kids were able to climb onto the quay below the Pescheria and dry out enough to transform by the time they reached the yard gate – where Giulia's parents were on their way out to meet them.

"Buongiorno!" Giulia greeted them.

Helena knelt down to give her a hug and wrap her up in a towel again. "Did you have fun, Passerota?"

"Yes! And Luca's grandmother made me a hat!" Giulia pulled it off to show her parents.

"That was very kind of her," said Helena. "I hope you said thank you."

"Of course I did," Giulia huffed.

"Just checking," Helena assured her.

Massimo opened the door into the house. "Were you warm enough down there?" he asked. "Did you get enough to eat?"

"Yes, Papà!" Giulia insisted, smiling. "I told you I'd be fine. Today we're gonna do the Christmas tree at Luca's house, and then can he and Alberto sleep over here tonight?"

"What about all those things in your room?" Massimo asked, looking at Alberto as he said it. "There's not much space in there, and you can't sleep in the treehouse when it's chilly out."

"We'll find spots for them," Alberto promised.

"Do you want some breakfast?" asked Helena, as the kids crowded into the small kitchen.

"No, thanks, we already ate," said Luca.

"I'd like some!" called the voice of Arturo Trota.

Helena had the door half-closed, but now she opened it again so everybody could look back out - Arturo was standing in the still-open gate. He was unsteady on his feet, being still new to walking, and was shivering as he transformed to human.

"Good morning!" he said.

"Good morning, Arturo," said Helena. "What brings you back here? I hope nothing's wrong."

"I was hoping I could have another cup of chocolate, please," Arturo replied through chattering teeth.

Helena sighed and smiled. "Of course you can, Piccione," she said. "Come on in and warm up. We've got some biscotti, too, if you'd like that."

"Yes, please!" said Arturo, hurrying to follow the others in. "What's piccione?" he asked the older children. "Is that something humans call each other?"

"It's a kind of little bird, like how she calls me Passerota," Giulia replied, as she and Luca both hid snickers behind their hands. In Genova, Helena had told both of them not to give scraps to the pigeons, because once the birds realized they'd found a source of food they would never go away. Giulia decided she would start counting, just to see how many days Arturo came back for cioccolata before he got tired of it.