Happy Mermaid Day! This chapter and the last were a lot of fun to write, and hopefully a lot of fun for you to read! MASSIVE thanks to always-comment-on-the-mutton (on tumblr) for her help on this chapter!

Only a couple more chapters! I'll be sad to see it end but you lovely readers have made it so much fun!

Emma had no idea what to expect when she went under the surface. She'd only seen Storybrooke's part of the ocean from the vantage point of the docks, the beach, or the Jolly Roger, so she really hadn't seen much.

She had expected the warm greeting—that kiss would likely never leave her memory, and Killian's reaction was everything she'd hoped it would be. It was the first of many similar kisses, she hoped: full of passion and intimacy and connection. She was honestly surprised that her magic didn't go crazy like his had.

"Now how about you show me what it's like to be a mermaid?" She asked him because she was genuinely interested in what he did down here all day. Any time she'd asked before, he simply brushed it off, but there had to be something down here worth seeing or doing.

His eyes sparkled, almost glowing, despite the darkness down here—what little sun was left barely illuminated the ocean floor. It suddenly struck her how their roles were somewhat reversed: it was his turn to teach her about his world now, and he was clearly, infectiously happy to do so.

He grabbed her hand, and with a dimpled grin, said, "Shall we, Swan?" He didn't give her a chance to respond before he was pulling her along (something she was grateful for, as she hadn't quite figured out how to work the brakes on this tail, as evidenced by the way she barrelled into him earlier).

"What are we doing?" she asked as they swam upward.

"I'm showing you what it's like to be a mermaid. And all mermaids have a perfect tail flip." He broke away from here when they neared the surface. "Just watch."

She'd seen him do this from the surface, but watching his graceful ascent and then quick descent from below, with a showy flourish and splash, was mesmerizing. He was plenty agile on two legs, and it was no different when they were replaced with a fin.

She was pulled from her admiration by him calling out to her, "Give it a go!" On her first attempt, she went too fast and far and shot straight out of the water, which was thrilling in its own way. Her second go ended up being more of a front flip that spiraled out of control, requiring him to catch her again in his sturdy arms (not that she minded).

He took a moment to guide her in the maneuver, pulling her alongside him as he did it slowly. He showed her just when to dive and, with the aid of hook and hand, just how to arch her back and fin to get the proper angle. Her skin tingled where he touched it and she was taken back to the ball they'd attended in the Enchanted Forest of the past; pick a partner who knows what he's doing rang in her head.

Third time was the charm, and she felt her tail fan out in the cool night air above the surface before diving back down. If she thought she had been in awe of him earlier, it paled in comparison to the look of pride and reverence on his face just then. "You're a bloody marvel, Swan."

She swam past his head, placing a kiss on his cheek as she went by. "Well, I have a good teacher." Even in the dim light, she could see his cheeks redden.

He didn't let whatever bashful feeling he had last long. "Come on, let's go to the harbor."

"What's there?"

"You'll see." He again grasped her hand, and headed off in the direction of the harbor.

She tried to keep up, but was easily distracted by the huge variety of flora and fauna she saw; she knew it was the ocean, but there were things here that she thought only survived in warmer waters. Huge swaths of kelp, soft to the touch as they flowed in the currents; brightly-colored coral on rocky ledges and dropoffs; the kind of ugly fish she thought lived in the tropics; and even a few anemones (she did learned something from Finding Nemo).

At some point, Killian found a white, flower-like plant, plucked it, and brought it over to her. Gently, he tucked a loose chunk of hair behind her ear and secured it with the flower. "Now you look like a true mermaid princess," he said softly, eyes filled with adoration. She could only smile (and blush profusely) in response.

With as beautiful as it all was, she could hardly believe that this was somewhere he'd want to leave, or a life he'd want to give up. For the first time, she thought back to what happened earlier that day, and part of why she'd come down here in the first place: he's my true love. But what if he feels more at home down here? Can I give up my life on land?

She wasn't long with her thoughts as they arrived at a massive anchor sitting in the muck. "Is that the Jolly Roger's?"

"Aye. I thought...we might do a bit of stargazing." He scratched that spot behind his ear in the middle of his thick dark hair (which was a bit longer than usual and flowing freely in the water), and gave her a slightly bashful stare from under his thick lashes.

"Down here?" She looked up; the waning moon cut a narrow path of light through the water, but she certainly couldn't make out any stars.

"No; on my ship." She could tell from his gentle tone that he was serious, so she wouldn't question it.

He drew her close to him. "Hold on," he said, and she could feel them rising through the sea...and kept going when they broke through the surface. Her arms were tight around his waist as he lifted them up in a column of water to the ship's railing, gently setting her down on it before taking his own seat and allowing the water to return to where it belonged.

"How was that?" he asked, a bit of a cocky smirk on his face that told her he was proud of it.

"Like a wet elevator," she jokingly replied.

"A what?" Oh duh.

"I'll take you to a mall sometime and show you one."

"I like the sound of that." She took that as a good sign as he pulled her close.

There would be time for serious conversations later. In that moment, she was feeling more relaxed and confident in both herself and them, as she nestled into the side of her true love, than she ever had.

Killian still couldn't believe this was real—that he actually had Emma by his side, and she had a tail. A bloody beautiful tail that sparkled alongside his in the moonlight as they sat close on the railing of his ship. Never in his many years had he imagined such a thing, or how happy it could make him.

A small nagging voice in the back of his mind reminded him it wouldn't last, but he was going to ignore it for the time being and just enjoy what moments they had together in these forms.

"Why stargazing?" He could see curiosity written across her otherwise content features.

"Swan, I spent the last several days confined below the surface, and as thrilled as I am to have you next to me underwater at the moment, I still miss some things above it." He glanced back up at the sky. "Stars have been my constant companions these past centuries; almost nothing can calm me more."

"Are they the same in every realm?"

"No, not quite; but I've yet to find a realm that doesn't have any."

A quiet calm settled over them as they both gazed at the sky and she lay her head on his shoulder, until she spoke up again.

"How did you learn to navigate with them?"

He laughed quietly. "So many questions tonight, love."

She playfully smacked her fin against his and smiled. "I just know so little about where you come from."

He wrapped an arm around her and squeezed; he couldn't remember the last time anyone truly cared to learn his background, possibly save for Henry. "Well, it was compulsory for a naval navigator to know how; we didn't have your GPS systems, I think they're called, so we had to rely on what was there. I was trained in the naval academy, and my brother taught me some before that."

"Liam, right?"

"Aye." Oh brother, how I wish you could see this. He had imagined more than once in the past few weeks what it would have been like had Liam also known their true parentage; had they been able to share the sea in this manner. He was finally something of a man his brother could be proud of, even if he didn't fully look it. And he owed so much of it to the glorious creature nestled at his side; his happy ending; his true love? The day's events weren't far from his mind, but they had plenty of time to discuss it.

The stars grew brighter as the hour grew later. They had both lost track of time, too caught up in simply being together. He noticed that she was having a hard time keeping her eyes open, and he too felt his eyelids grow heavy.

"Do you need to head home, love? Wouldn't want to worry your parents."

"No; I told them not to wait up," she said with a slight smile. "I was hoping—" a yawn interrupted her thoughts. "I was hoping that...I might be able to stay with you tonight." She blinked up at him shyly. "You know, get the whole mermaid experience."

He was momentarily awestruck, and had to make a conscious effort to not let his jaw drop. "Of course, Swan," he said, probably too quickly. He offered his arm. "Allow me to escort you back to your lodgings." She smirked back and grabbed on. "Alright, hold tight."

He used his good hand to launch himself off the railing and could feel her squeezing his arm and trailing just behind. At the last second, he raised his right arm ahead and dove into the water gracefully and nearly soundlessly; the splash he heard almost simultaneously suggested that Emma didn't have quite the same re-entrance.

A chuckle escaped his mouth as he saw her regaining her bearings, hair a mess around her head.

"Jeez, give a warning next time!" She was trying to be angry but the laughter in her eyes told him otherwise. "Show off," she muttered as she swam past. He watched her for a moment before catching up.

She was still getting used to having a tail, he could tell—she didn't have the same ease of movement he saw in Ariel and likely possessed himself. But she had more control than when she first dove under the sea, and if the expression on her face was any indication, she clearly enjoyed it.

Her childlike awe at everything was just as infectious on the way back to the cove as it had been going to the harbor. She was so enraptured with everything that had become old hat to him over the past weeks that he felt as if he was seeing it for the first time, too. He was especially taken with the way she swam through the many kelp forests, letting the fronds gently caress her skin (he never realized until that moment that it was possible to be jealous of a plant).

He couldn't describe how happy it made him that she was enjoying herself down here. Ever-present pessimistic thoughts in his mind had allowed doubt to slip in that the enchantment on his father's cuff wouldn't be able to be restored, even though he had full faith in Emma's and Regina's capabilities. But if, for some reason it didn't work, at least they had this. He certainly didn't expect her to give up her life and family on land to be with him, so he was thrilled that there was still some way for them to be together. I owe Ursula a serious debt of gratitude.

When they arrived back at the cove, she paused and glanced around, biting her lip. "So...where do you sleep?"

He responded by drifting down into the bed of kelp he'd become all too familiar with, placing his hook behind his head. "Right here."

"Really?" Disbelief was written on her face.

"Aye, love, come—it's actually quite comfortable." He patted his hand on the foliage next to him.

She wore a look of doubt, possibly mixed with pity, as she slowly laid down next to him. But that quickly changed to a peaceful smile when she sank into the surprisingly plush greens. "Ok, I believe you."

She tucked into his side as he wrapped his arm under her shoulder, laid her head on his chest, and reached across to lay her hand over his racing heart. When she coiled her tail around his, he thought his heart might beat out of his chest altogether (at least she's here to catch it, he joked to himself). Emma had become much more open with her affections in the past few weeks, but this was a whole new level—one he hoped they stayed at.

They laid there for some time, soaking in this new intimacy. Despite their earlier drowsiness, neither one seemed to drift off very easily; Killian knew his adrenaline was running due to their proximity, and he wondered if that might be the cause for her insomnia. But when when he glanced down at her face, she was focused on something; her brow was furrowed in the tell-tale sign of an internal debate.

"You should get some rest, love; it's been a long day."

"That it has. A lot happened. I was just...mulling it all over."

Is she thinking about...what I've been thinking about? He didn't want her to feel pressured into a heavy conversation this late. "Swan, don't worry about it now; we can—"

"No, wait. I want to." She closed her eyes in concentration, as if she was mustering the strength for something. He swallowed, having no idea what was to come.

She finally opened her eyes and stared into his, her jade irises appearing an even darker shade of emerald in the depths of the water. "Killian," she said at long last.

"Yes, Emma?" He hoped the calm of his voice hid the panic that was lying behind it. Whatever she was gearing up for was clearly a big deal.

"Killian, I...I love you."

It hit him like a tidal wave; the realization of the words that had just slipped out of her mouth washed over him, and even though he was breathing underwater, he felt like he could drown in them. He could feel the ridiculous grin that spread over his face, but he didn't care in the slightest. She loves me.

"I love you, too, Emma. More than you could possibly know." He pulled her in closer, if that was possible, and placed a gentle kiss on her forehead.

"Um, actually, I did know, kind of."

Her cryptic words didn't dampen his mood—she loves me, she bloody loves me—but did pique his curiosity; he raised an eyebrow in question.

"Today, on the dock, when I saved you; that was—"

"—true love's kiss?" he finished.

She looked up at him with a shy smile and love in her eyes. "Yeah." But then her eyes narrowed. "Wait, you knew?"

"I had a hunch."

"Why didn't you say anything?"

"I didn't want you to feel any pressure, love."

There was a calm in her eyes for the first time since they'd came down here. She pressed a small kiss against his jaw and whispered, "Thank you." She tucked her head under his chin and let out a content sigh.

I could stay here forever. What more did he need, but the woman he loved—and who loved him back—at his side? It was all he had dared to hope for, but the fact that they were true love was beyond his dreams (and far beyond anything he thought he'd ever get or deserve).

The future was likely to be complicated, but there'd be time to discuss where they went from here. For now, he was content to hold Emma close, and enjoy the first night of many with his true love.

Thanks for reading! Let me know what you think!