Set about a year after Hook comes to Storybrooke; he and Emma are now a couple living together with Henry. Gold wants someone to test a spell on, Emma owes him a favor still, but Killian isn't about to let her get hurt, so he volunteers instead. Spoilers for everything up to 2x09, also AU because it the show Emma can cross the town line. I don't know how long is this gonna be because I don't usually write long fics, but I think it's got potential to have about 20 chapters. I can't remember when was the last time I shipped something as hard as I do Captain Swan, so... Hope you enjoy.

Killian Jones steps over the town line, and the world goes black. It's like someone had flipped a switch, turning out all the lights, only it's worse, because the darkness is absolute.

"Killian?" Emma says his name softly, but she can't hide the fear in her voice, not from him. He turns around and grins in her general direction, to let her know he's still the same, that he can still remember everything.

"Do you know who you are?" Rumpelstiltskinasks, and Killian nods.

"I do. There's just one problem", he tells him, amazed at the fact that he sounds as cool as ever, even though he feels adrift in the sea of black, without a single star to guide his way. It's only when Emma speaks that he feels less alone, and not so very lost anymore, her voice like a beacon in the night over stormy sea.

"What's wrong?" She's coming closer, and he puts out his hand to keep her on the safe side, because he knows she would come to him no matter the danger if she thought he needed her help.

"Mind the line, miss Swan", Rumpelstiltskin says, and Emma stops moving. Still, she's so close he can smell her; wild flowers in her shampoo and something else that he can never put his finger on.

"What's the problem, Captain?"

"I can't see," Killian says, cringing inwardly at the way his voice breaks. He's fighting the urge to rub his eyes because he knows it wouldn't help dispel the darkness. This is something magical, and there's nothing wrong with his eyes that rubbing can fix.

"What?" Emma gasps, and she's even closer now, probably toeing that line no one can cross without losing their memories. Except he did, just now.

"Emma, stop", he says, hoping he's facing her and not empty air. "Magic never comes without a price. Isn't that right, Mr. Gold?"

"You knew this would happen?" Emma moves away, probably to get into Rumpelstiltskin's face, which is fine with Killian because Rumpelstiltskin always stays at least ten feet from the line.

"I did. The Captain is right; you can't get something for nothing."

"So in order to make a spell that would allow you to cross the town line and keep your memories, you were ready to sacrifice your sight?" Emma sounds incredulous, and it's exactly how Killian feels, because he never thought the Dark One was capable of sacrifice, for anyone or anything.

"Yes," Rumpelstiltskin answers, and he sounds so calm and completely sincere, that even Killian is tempted to believe him, but he knows better than to trust a crocodile.

"Okay. You tested your spell, it works, now give me back my sight", Killian demands, trying for nonchalance. Emma comes back within arm's length, so clearly he's fooling no one.

"You're gonna be fine in a minute", she whispers, for his ears only, and he knows she can see through his bravado as easily as he can through hers.

"Just come back to this side of the line, Captain, and you should be able to see again," Rumpelstiltskin says offhandedly, as if his mind is already busy with other things.

"Should?" Emma sounds exasperated and anxious, and Killian gets a bad, bad feeling, but what choice does he have? She can't come to him, and he's not going out in the world without her, blind or not.

Taking a deep breath, he outstretches his hand toward Emma, their fingers meet and entwine, she tugs him forward and he steps back over the line.

The world is black, but this time, both inside and out.