The rain was letting up and the sun was starting to come through as Signor Granchio dropped them off again at the Gennaris' house, but it was too late for them to go to Pompei Scavi now. If they tried, they'd be waiting in line forever, and if it began to rain again they would have to leave. Carlotta came to the door to greet them, and thanked Granchio for bringing them home. She didn't say anything about her earlier fears, but the relief in her voice was audible.

"Your timing is pretty good," she said, as Alberto and Luca took off their raincoats and boots.

"It is?" asked Alberto.

"Well, the rain is stopping," Carlotta said. "We can go to the Archaeological Museum if you'd like. But also, your grandmother wants to talk to you."

"Really?" Nonna Sofia was probably the only member of this family that Alberto would actually be happy to see.

"She's in the kitchen," said Carlotta.

Nonna Sofia was waiting there with a cup of coffee, and when the boys entered the room she stood up to give each of them a hug. These were longer and tighter than the ones she'd greeted them with at the train station when they'd arrived – did that mean she liked them better now than she had then? Alberto hoped so.

"Carlotta said you two went to Portici this morning to ask about your father," she said to Alberto.

"Yeah, but he wasn't there and nobody'd seen him," Alberto replied. He did not mention the fact that he might have lost his father his job as well as his girlfriend.

"Oh, dear," said Sofia. "I wonder where he's gotten to. I'm going to have a few things to say to him when he gets home, that much is for sure." She didn't sound angry, though. She still sounded worried, as if she wasn't sure he was going to come home. "That's not why I came, though. Flavia says she wants to talk to you."

"Really?" Luca asked, taking an eager step forward. "What about?"

"She wouldn't say," said Nonna Sofia, "but she'd like you to stop by her fathers' place."

Luca looked at Alberto with a hopeful smile, which Alberto returned. Even if she wouldn't say the exact reason, it had to be that Flavia had decided to forgive them. What else would she have to talk about with them?

"We'll go right now," said Alberto. Luca nodded.

Since the day had been wet, Carlotta had been doing indoor chores like laundry. The boys' swimsuits had been washed, but had not yet been put in the clothes dryer. They put them on wet and ran down to get in the water, with Nonna Sofia following them. All three swam out to the sunken boat where Uncle Leonardo and his family lived.

They arrived to find Flavia in the middle of a lesson. She was sitting with a slate and chalk, while Uncle Giorgio helped her to solve some math problems. Luca saw this and immediately stopped, not wanting to interrupt, but Alberto couldn't think of anything more boring than the math Massimo had tried to teach him – even if it had turned out to be useful when he needed money for things – so he was happy to announce himself.

"Hi, Flavia!" he called out.

The boys' didn't know Flavia's own feelings on arithmetic and her reaction didn't give them any clues. She looked up and immediately set the slate aside to meet them – but she did not smile. She looked at Uncle Giorgio, then at Nonna Sofia, and then removed the lumpfish that had stuck themselves to her arms and one foot and put them on the discarded slate, before going to greet her guests as if determined to get it over with.

"Hi," said Luca uncertainly.

"Hi," said Flavia.

"Are you okay?" Luca asked.

"I'm fine." She looked at her father and grandmother, then gestured for the boys to follow her. "This way."

She paused to pet her lumpfish and promise them she'd be back soon, then led the boys around behind the boat. There was some privacy there, among the tall multicoloured seaweed. Flavia found a clearing big enough for all three, then folded her arms across her chest, faced the boys, and said, "I'm still mad at you."

"Oh," said Luca, disappointed.

"Why do you wanna talk to us, then?" asked Alberto. Had they really come here just so she could tell them that?

"Papa Leo said you were worried about your dad," said Flavia.

"Yeah?" Alberto said.

"I know where he is."

Alberto's eyes widened. "You do?"

"Yes," said Flavia. "He told me I'm not allowed to tell Nonna, I can't tell Papa Leo or Papa Giorgio, and I can't tell any of my aunts or uncles, but he didn't say I can't tell you."

"Where is he, then?"

Flavia looked around again to make sure nobody was watching them. "You can't tell," she warned, "because I'll be in trouble if they find out I've been there again."

Alberto looked at Luca, who nodded. They didn't need Flavia to be any more angry with them.

"We promise," said Alberto.

"Cross our hearts," Luca agreed.

Flavia came a little closer, and spoke in a whisper. "He's in the submarine.'

Alberto's heart beat a little faster. If Giancarlo were hiding out in the submarine then he wasn't in trouble – in fact, he must be there because he was trying to stay away from the humans looking for him. But the submarine was a terrible hiding place. What if it collapsed, like what had happened when Alberto touched the skeleton? One of Giancarlo's few firm rules while Alberto was growing up was that you didn't go into shipwrecks unless somebody was out there waiting for you.

"What's he doing there?" he asked.

"You'll have to ask him," Flavia said, "because all he told me was that he needed a place to hide where nobody will ever look for him, and he knows I'm the best at hiding. Everybody thinks it's too dangerous to go there."

"Thanks," said Alberto, and then thought of something. "Does he hang out with you?"

"Not really," said Flavia. "He lives at Nonna Sofia's house on land and he works with humans. But he brings me presents sometimes."

Giancarlo had used to bring Alberto small gifts when he'd been away for a few days. Here he probably did it for all the kids, like how some of the children in Portorosso had aunts or grandparents they rarely saw but adored just because they always got a gift from them. Giancarlo probably liked having an easy way to make kids like him.

"Thanks," he told Flavia, then took Luca's hand. "Let's go."

Luca didn't have to ask where they were going, but he was surprised by the urgency. "Right now?"

"Yes," said Alberto.

"People are gonna wonder where we are," Luca pointed out.

"Then we'll think of what to tell them when we get back," Alberto replied. He needed to know what was happening, and his father needed to know that another chance was possible.

"Thanks, Flavia!" Luca called back to her, as Alberto dragged him away.

They swam across the seagrass meadows and reefs Flavia had showed them before. Alberto spared a thought or two for what Nonna Sofia would say if she knew they were going exactly where she'd told them not to, but he wasn't too worried about it. She wouldn't find out if he could help it, and even if she did, it seemed like she didn't stay mad about things.

Soon they made out the shape of the submarine in the gloom below them. Luca and Alberto split up and began peeking in openings to look for Giancarlo. He was not in the back with the skeleton, which was a relief, nor was he in the torpedo tube where Flavia had mentioned liking to hide. Eventually, Alberto was forced to conclude that by 'in the submarine', Flavia really had meant inside the rusting wreck. He and Luca found some glowing jellyfish to use for lanterns, and cautiously began exploring the interior.

They didn't have to go far. Giancarlo was holed up in what had once been a dormitory, although the mattresses and blankets had rotted away long ago, leaving only the barnacle-caked metal skeletons of the bunks. He had set up a few jars of phosphorescent algae, and by their dim blue-green light he was sitting with his back to the door, cross-legged on the floor playing a game of Klondike with a deck of mismatched cards. He was still dressed in the clothes he'd worn to take the boys to Portici, minus only his jacket and hat, which were draped over one of the old bunk railings.

"Signor Scorfano?" asked Luca.

Giancarlo yelped and turned around, then pushed his cards aside and swam up to glare at the boys. "What the shells are you two doing here?" he demanded. "Alberto! What did I always tell you about going inside shipwrecks by yourself?"

"It didn't stop you from doing it," Alberto pointed out. "Or from playing cards, after you promised Nonna Sofia you wouldn't!"

Giancarlo snatched up one of the cards, which was fluttering in the water where he'd stirred up the current by swimming. "I promised I wouldn't bet on cards. This is solitario. There's nobody to bet with. Come on, what if this place collapses? Get out! Get out!" He shooed at them.

"Why should we get out when you're going to stay?" Alberto demanded. "You're setting a bad example!"

"Did your grandmother tell you to say that?" Giancarlo asked.

"No. Nonna Sofia doesn't know you're here."

That seemed to be a surprise. "She doesn't?" Giancarlo asked. "Who told you, the... Flavia! That little brat, she promised!" he growled. "I gave her a whole bag of strawberries. I would have thought Leo, out of all of us, could raise a kid who could keep a promise!"

"She said she promised not to tell her dads or her nonna," Luca pointed out.

"Yeah, she didn't promise not to tell us," Alberto agreed.

"I didn't think I had to make her! I thought that was implied!" his father snorted. "She said she didn't like you, anyway. You dragged her out of the water."

"We apologized!" huffed Alberto. "Why are you hiding here?"

"Why are you here looking for me?" Giancarlo asked. "Didn't I tell you about how I nearly starved to death in a collapsed shipwreck before your mother found me? Go on, out! Out!"

Alberto folded his arms and wrapped his tail around one of the bedframes. "I'm not leaving until you do."

"And go where?" his father wanted to know. "I can't go back to Ma's house. I don't want her involved in this."

"Who are you hiding from?" Alberto asked.

"Who do you think?"

"Sir?" Luca raised a tentative hand as if in school. "If you need to hide, we know a less dangerous place."

"We do?" asked Alberto, confused – but then he realized he knew what Luca meant. "He's right! We know a perfect place! You want us to leave, or not?" he asked his father.

Giancarlo looked suspicious, but he collected his hat, jacket, and cards, and followed the two boys out of the submarine wreck and up to the island with the remains of the castle on it. He kept low to the bottom the whole trip, not wanting to be seen. At the island they climbed the steps, and Giancarlo looked around skeptically at the ruins the boys showed him.

"There's no ceiling," he said. "If it rains, I'm gonna get wet."

"There's no humans here to see you," Luca pointed out.

"It'll still be cold," Giancarlo grumbled.

"We'll bring you a tarp or something," Alberto decided, "and some blankets."

"What about food?" his father insisted. "Flavia's been bringing me stuff to eat, but she can't come up here. Or... she technically can, but I don't think it's good for her."

"We'll bring you that, too," said Alberto, "but you have to tell us what's going on."

Giancarlo sat down on a boulder and wrung water out of his hat. "You know perfectly well what's going on. Did you think Godin just tracked me down for a friendly chat? Him and his cronies are trying to force me to help them out with something, and I want no part of it." He sighed, his shoulders slumping. "I promised Ma I wasn't gonna get into any more trouble. She told me I could only live at her house as long as I behaved myself. She told me this was my last chance. If I screw this up, I lose everything." He gave Alberto a pleading look.

Alberto smiled – this part, at least, was good news. "No, you don't."

"Yeah, I do. Ma said..."

"She didn't mean it, though," said Luca, then realized he'd interrupted and tried to apologize by adding, "Sir. She didn't. Alberto thought we were gonna have to leave after we... um..." he stopped again, remembering Alberto getting upset with him for nearly telling the Gennaris the boat story.

"After we pulled Flavia out of the water," Alberto said. His father didn't need to know he'd nearly set Celia on fire. "We were gonna get a train and go back to Portorosso, but when Nonna Sofia found us, she wasn't even mad. I mean, she said she was mad, but she was just happy we were okay."

"And now it's fine," Luca agreed. "Flavia even forgave us!" Alberto could see his friend crossing his fingers behind his back.

"If you go home she'll help you," Alberto said. "I promise."

Giancarlo sighed. "Alberto, I'm not thirteen years old anymore."

"I'm fourteen," said Alberto.

"Right, right. The point is, I'm a grownup and I should know better." Giancarlo sighed and looked out at the sea on the horizon. "That's what she told me."

There was an uncomfortable silence.

"Do they want the diamonds?" Luca asked. "Signorina Sorrentino thought they wanted the diamonds for the Queen of Danimarca's tiara."

"Yes, that's exactly..." the colour drained from Giancarlo's face mid-sentence. "You told Polly?"

Luca clapped both hands over his mouth.

Giancarlo stood up. "What did you tell her?" he asked urgently.

Luca was determined to say nothing more. It was up to Alberto. "We just went to ask her if she'd seen you," he explained, "because nobody in the sea had, so we thought you might be on land. Aunt Diana laid her egg and you didn't even come to see. So we asked Signor Granchio to take us back to Portici and ask her. We told her you'd seen a guy you used to know who was a criminal, and she decided she had to tell the Signori Rossi..."

"What?" Giancarlo grabbed Alberto's shoulders. "You didn't tell them, did you?"

Alberto wiggled free. "Don't touch me!" he ordered.

"We kind of had to," Luca said, coming to his friend's defence, "because if we didn't then Signorina Sorrentino would have!"

Giancarlo stepped back and put a hand over his eyes. "Great! Why didn't you just walk in there and tell them I'm a sea monster, too?"

"It was kind of an accident," said Luca.

Giancarlo was not interested in him. "Didn't Ma tell you I'm supposed to be keeping a job?" he asked Alberto. "What, did you just come here to ruin my life?"

"I thought you were in trouble! I wanted to help!" shouted Alberto. "Nonna Sofia wants to help, too!"

"I don't need help!" Giancarlo yelled back. "And I don't want help!"

"Okay, fine! We'll leave!" Alberto grabbed his friend's arm. "Come on, Luca."

He expected Luca to protest that they couldn't just leave Giancarlo there, and was ready to ignore it – but Luca was too embarrassed by repeatedly saying things he shouldn't have, and kept quiet. Giancarlo did not call for them to come back, so the two boys continued down the steps into the water.

"What are you gonna do now?" Luca asked, as they lingered in the sea next to the island.

Alberto scowled. For a moment, he really just wanted to say they were going to go back to Portorosso and never even look at the Gulf of Napoli again, but that would have meant his family talking more about how he was just doing things for attention. "We're going back to Flavia's," he decided.

Luca swam after him as he set off. "Are we gonna tell them about your father?"

"He said he didn't need help," Alberto said.

"I kinda think he does," said Luca.

Luca was right, really... Giancarlo couldn't sit on that island forever. He needed to know he wasn't all alone. Nonna Sofia would want to know he was okay. Giancarlo had made Flavia promise not to tell, but he hadn't made Luca and Alberto.

"You think we should tell Nonna Sofia?" he asked Luca.

"Yeah," said Luca. "I'm sure she can help somehow. If nothing else at least he won't have to sit in the rain on that island." Through the rolling surface of the ocean, they could see clouds closing in again.

Part of Alberto hated the idea of asking for help. He'd never needed help with anything in his life, and... well, no, that was not true. Alberto had needed help with a lot of things. There'd just never been anybody he could ask for it until recently, when he'd met Luca and then Massimo and Giulia. Even now, he was so used to doing stuff on his own that it seemed wrong to ask somebody to help. Was that how Giancarlo felt right now?

If it was, then he probably shouldn't. This situation, with thieves and diamonds and queens involved, was way too much for one person to try to deal with. It was certainly too big for Luca and Alberto. They were just kids. This was a grown-up problem.

Again, Alberto internally rebelled against the thought. He was a grownup, or nearly so. He was fourteen! His father had said he was old enough to be on his own and that had been ages ago. At the same time, however, the idea that this was a problem for adults brought with it an immense wave of relief. If that were true, then he could just pass it on to somebody else and be free, and he and Luca could get back to doing things like exploring the bay and seeing the stuff in the travel book.

"Okay," he decided. "We'll tell her."

Luca nodded.

As they approached Uncle Leonardo and Uncle Giorgio's home, Alberto started to hear people calling their names, and realized rather belatedly that they'd been gone a long time. Maybe he shouldn't tell. Maybe they'd just get into more trouble, and they didn't need that. Maybe they should just hide... but they'd have to come out eventually, and then people would only get angrier at them. Alberto looked back at Luca to see what he thought.

"They're gonna be mad we ran off," he said.

"Yeah, but only a little," said Luca. "Silenzio, Bruno."

"Silenzio, Bruno," Alberto echoed, and then called out. "Here we are!"

Nonna Sofia dashed over, a hand on her chest. "Heavens!" she exclaimed, giving each of them a hug. "You boys have got to stop vanishing like that! You give me a heart attack every time!"

"Sorry, Ma'am," said Luca.

She put an arm around each of them, as if afraid they'd disappear if she looked away, and escorted them back to the sunken boat. Flavia was there, sitting sullenly on the railing with her arms crossed over her chest and her three lumpfish arranged on either side of her, a picture of defiance. Her fathers were waiting with her, and Carlotta and Celia joined them shortly after.

"See?" Flavia said. "They're fine."

"I can see that, Angelfish," said Uncle Leonardo patiently, "but you didn't know that until just now. What if they hadn't been?"

"We asked Flavia where you'd gone, but she said she'd promised not to tell," Nonna Sofia told the boys. "Where did you go that you had to make her promise that?"

"We didn't," said Alberto. "She didn't promise us. She promised my father."

Uncle Giorgio threw up his hands. "What have I told you about your Uncle Giancarlo?" he asked his daughter.

"He's nice to me!" said Flavia. "He doesn't ignore me like the other grownups do."

"It's not Flavia's fault," Alberto repeated.

"It really isn't," Luca agreed.

"We're going to have a word about this later, young lady," Uncle Giorgio went on.

"Hey!" shouted Alberto.

People turned to look at him, startled.

Alberto arched his back a bit, the underwater equivalent of drawing himself up to his full height. He needed them to listen to him, both to get Flavia out of trouble and to get Nonna Sofia to help his father. "Giancarlo is hiding," he announced. "I told you he was missing. He was hiding in the sunken submarine because he doesn't want his human friends to find him. He helped them rob a bank ages ago, and now they want him to help them steal some diamonds."

This was greeted by a stunned silence.

"He robbed a bank?" Leonardo asked, horrified.

Nonna Sofia sighed. "Yes, he did. We're trying to move past it."

Luca put both hands over his own mouth again. If Alberto were now blurting out things he shouldn't, Luca was just not going to say anything.

"Luca and I saw the men at the train station when we tried to run away," Alberto went on. "Flavia showed him the submarine as a place where nobody would look for him, and she was bringing him food. He didn't want to tell anybody because he was afraid Nonna Sofia would throw him out. Luca and I made him move up to the island with the old castle, because the submarine was too dangerous." Was that everything? Alberto hoped it was everything. "I said I'd bring him a tarp and blankets so he could stay warm and dry, but I also told him that if he goes back to Nonna Sofia's house, she won't be mad." He looked at his grandmother, hoping this was the right thing to do. Telling the Rossi brothers had felt wrong. Telling Nonna Sofia felt... Alberto wasn't sure.

But she smiled at him, and gave him another hug. "Thank you, Alberto. I've been very worried about your father, too, although I haven't wanted to admit it. On the island near where Carlotta feeds her sharks, you said?"

"That's right." Alberto nodded.

"Thank you," she repeated. "Let me just gather some things, and I'll head right out to him. And thank you, Flavia, for telling Alberto." She went and stroked Flavia's fins, then kissed her forehead.

"I had to tell somebody," Flavia said. "It just couldn't be anybody he made me promise not to tell. I would have felt bad."

"You shouldn't," said Uncle Giorgio. "You don't owe him anything. Robbed a bank, eh?" he looked at Leonardo. Leonardo just sighed.

Nonna Sofia darted off back to her house to put together her care package, and Alberto breathed out some bubbles as he sighed with relief. Yes, that had been the right thing. It felt good. They were free now. They could do whatever they wanted without worrying about Alberto's father.

Celia came closer to look at the three lumpfish that were stuck to the railing of the sunken boat. Flavia peeled one off and put it on Celia's arm, which made her giggle.

"Mamma, can we get some?" Celia asked.

"I don't think so, Guppy," Carlotta replied. "They don't look like they'd do very well in an aquarium, and we couldn't just let them live by themselves in the sea. This isn't their natural habitat."

"That's right," said Uncle Giorgio. "You've got to be very careful with creatures who are far from home. They can do a lot of damage in an unfamiliar place." He glanced at Alberto, who winced.

Flavia sighed, probably thinking of the scorpionfish – but she also kept looking at Carlotta, watching the white fins on the left side of her head drift on the current. When Carlotta noticed, Flavia quickly looked away. Carlotta reached up and self-consciously touched the white patch around her eye, then came and moved the lumpfish so she could sit beside Flavia.

"This is called vitiligne," she said, offering a hand for Flavia to see the white scales and webbing. "It started to show up when I was about your age. We didn't know what caused it at the time. I found out later it's a problem with my skin, where it doesn't make pigments anymore."

"Does it stay when you get out of the water?" asked Flavia.

"Yes it does," Carlotta said. "I have to be careful not to get sunburned."

"Aunt Diana said people used to be mean to her about it when she was little," Alberto offered.

"Really?" Flavia asked, looking up in surprise. "It's so pretty, though!"

Carlotta laughed softly. "It's not so much that they were mean on purpose as that they wouldn't stop staring at me, or suggesting ways to 'cure' it. I was very ashamed of it for a long time, but when I got older and learned what caused it, I realized it was just the way I am and it doesn't need to be cured."

Flavia nodded, but lowered her head again.

"You hear that, Angelfish?" Uncle Leonardo asked encouragingly.

"It's different," said Flavia.

"How is it different?"

"She can still do everything everyone else can do," Flavia said.

Carlotta looked at Giorgio and Leonardo with an apologetic expression. She'd tried her best. "You're welcome to come and feed the sharks with me and Celia any time you like," she promised Flavia. "Luca and Alberto have been telling me about how much you like animals."

"Thank you, Signora Gennari," said Flavia.

"Alberto's dad said he gave you strawberries in exchange for showing him the submarine," Luca spoke up. "Did you like them?"

"Yeah, they were nice," said Flavia. "I don't have any left, though. He said they go bad quickly, so I ate them all."

"That's why you didn't want your dinner," Uncle Giorgio said crossly. "We try to discourage her from talking to your father, Alberto. He's a bad influence."

"No, he's not," said Flavia. "I mean, I know he's done bad things, but he doesn't tell me to do bad things."

"Sometimes you don't know they're bad things until after you've done them," said Alberto, remembering how his father had talked him into helping him escape from prison.

"Not telling your Nonna and us that he was hiding in that submarine was a bad thing," said Uncle Giorgio. "What if it had collapsed on him and he'd gotten hurt or killed in there?"

"I would have told about that," said Flavia. She turned to the boys again. "I never even met Uncle Giancarlo until he came home last year. He'd been gone since before Papa Leo and Papa Giorgio found me. He was nice at first, and I was afraid he'd stop when he found out there's something wrong with me, since he spends so much time with humans. He didn't, though. He even told Lucrezia to go get stuffed."

"He did?" asked Alberto.

"Yeah, she went and cried to Aunt Bettina about it." Flavia rolled her eyes. "He brings me coco sometimes, and he gave me some shells that the jewelry company didn't want. And he once brought me a banana, but I didn't like it. It was very bitter."

Alberto immediately knew why not – he'd had a similar problem with oranges. "You're supposed to peel them."

"I'll try that next time," Flavia promised. "Is he really going to steal diamonds?"
"No," said Alberto. "He knows that if he tries he'll end up going back to prison." Alberto had seen very little of prison, but it had looked terrible. Nobody deserved to be shut up in a place like that no matter what they'd done. He wouldn't even have wished it on Ercole.

"Your Nonna won't let him," said Luca, and then brightened as he got an idea. "You know what we should do now that the grownups are looking after it? We should go to Baia!" He turned to Flavia. "When Alberto asked me to come here with him, I went and got a book at the second hand shop that was all about things you can see and do in Napoli, and one of them is an ancient city with statues and mosaics and all kinds of things, two thousand years old! I'd even near Bacoli, which is where the Gennaris live. We should go see that!"

Flavia looked at him, unable to figure out why he was saying this to her. "Have fun, I guess," she said.

But Alberto knew what Luca was getting at. "That's the place where the runs are underwater, right?"

Luca grinned. "Yes! The town fell into the ocean after an earthquake and it's still there, and because the weather is bad today there won't be humans diving! You want to come? I bet Signora Gennari knows where it is!"

"I do," said Carlotta. "I've even been there, but only to the part on land. I keep meaning to look at the underwater ruins but I haven't gotten the opportunity. It sounds lovely." She smiled at Flavia. "You're welcome to join us."

"Can I?" Flavia asked her fathers.

"I don't see why not," said Uncle Leonardo.

"I'll come along, too," Uncle Giorgio decided, with a suspicious look at the boys.

Celia didn't seem happy, either. "Is this gonna be more rocks, like at Pompei?"

"Yes, Guppy, but they're rocks underwater, so there'll be fish for you to play with," Carlotta promised, "not like in Pompei where you're not allowed to pet the dogs. There are a lot of stray dogs in Pompei," she added by way of explanation. "Many of them have parasites and others aren't that friendly. Let me just leave a message with the neighbours so that Zia Sofia won't wonder where we've all gotten off to." She gathered up Celia and set off for shore.

"I'm still still mad at you, by the way," Flavia said once she'd gone.

"That's okay," said Luca.

Alberto nodded. It seemed like she might forgive them eventually. They would just have to give her time.