If you recognise it, it's not mine.

There's nothing quite like waking up to the sound of a teenager crashing into a potted plant in the middle of the night. It was dark in the apartment, but I could see Paul stumbling around in front of me, trying to flick on the lights and pull on a dressing gown at the same time.

"I'll deal with it," I said, leaning over to switch on the bedside lamp.

Paul blinked drowsily, giving me a look somewhere between relief and concern, which was sweet. "It could be a burglar or something, Sally. Maybe I should-"

"It's probably Percy tripping over on the way to the bathroom," I said, hoping he was still asleep enough to forget that Percy was supposed to have left for college last week and wouldn't ask questions. Sometimes, pure teenage clumsiness is harder to explain than myth-related accidents, especially when the two are combined on a regular basis.

"Oh," Paul said. "You sure? I can still go-"

"It's fine." I nudged him back towards the bed and shut the door behind me, taking a breath before switching on the main light.

The potted plant had indeed been crashed into, knocked over, and broken- just not by the teenager I'd been expecting.

"Oh," a small voice said. "Um..."

"Nico?"

The boy was crouched on the floor, scooping bits of broken pottery up with his hands. "Oh," he said again, turning his head to look at me. "I'm sorry, Percy gave me your new address but I wasn't really sure where it was, and I kind of..."

It had been a while since I'd seen Nico. How old was he now? A couple of years younger than Percy. Fifteen, maybe.

"I'll fix it in the morning," I said gently, taking the pieces of plant pot out of his hands.

"Fix it?" He looked at the pieces doubtfully, and I shrugged.

"Throw it out. I've been meaning to do that for ages anyway- it was a Christmas present from Paul's mother, and she's not the best at colour schemes." He glanced around nervously, and I took his hand, guiding him to his feet. "Trust me, you've done us a favour."

He looked healthier than I remembered, less skinny, a little taller, not quite so pale. He seemed tired, though, heavy-eyed and hopeless. I led him through to the sitting room, nudging him to the couch.

"Do you want anything?"

"I'm fine." His voice was slightly hoarse, and he was fidgeting with the skull ring on his finger. I got him a glass of water.

"So, how are things at camp?" I asked, as if this was a normal conversation not taking place at two in the morning.

Nico shrugged. "Quiet, mostly, now Percy's gone." He smiled slightly, tapping his fingers against the side of the glass. "I go to Camp Jupiter sometimes, to see him and Hazel and Annabeth and the others. They seem okay."

I nodded. "And how are you?"

He twitched, like he wasn't expecting the question. "Me? Oh, I'm... I'm fine."

"Which is why you're sitting on my couch in the middle of the night."

He looked down. "Sorry."

"Nico, it's not a problem. I've told you before, you can come here whenever you like. But if there's something I can help you with, I want to know. This isn't anything..." I waved a hand vaguely, and he shook his head.

"No, not really." He set the glass down on the coffee table, carefully, as if he was afraid of breaking it. There was a silence; we could hear Paul snoring from the bedroom.

"I had a fight with Will," he blurted eventually, twisting the ring on his finger again.

It took me a second to place the name. "Will- your Will? What about?"

He hesitated again, and I crouched down in front of him. He'd had a haircut; you could see his eyes now. They were clouded with tears, clinging to long lashes as he tried to blink them away.

"It's just... After the whole Gaia thing, I was, you know, kind of half dead, and he was the one taking care of me, and that's how we started talking properly." He stopped, shaking his head. "And that was a while ago, and I'm fine now, really, but he's still... We had Capture the Flag, and someone managed to drop their sword on my foot, and while I was in the infirmary, he kept saying stuff about how I needed to be more careful and that he worries about me, and it's just..." He broke off, dragging a hand across his face. "He's always been the one taking care of me, and it's like... I don't know."

"You feel like your whole relationship's built on him helping you?" I guessed, sitting down beside him.

He shrugged. "Kind of."

"Is that what you fought about?"

"I don't even know if it was a fight, just that I was supposed to be teaching sword fighting, and he warned me to be careful. It was just casual, and he meant well, but it just made me really... not angry, exactly, but it's like he doesn't believe I can handle myself, and I can, really."

"So why are you here?"

Nico slumped a little, sinking into the cushions. "I guess I just needed some space," he said unconvincingly. "I couldn't sleep, and it got kind of cold, wandering about, and I'm tired and I couldn't go to Camp Jupiter because they're in the middle of some ceremony thing and they're all so busy and everything's just gone so..." he trailed off, yanking at his ring so hard it came off his finger, landing on the coffee table with a clink.

"Do you want a hug?" I asked quietly after a second, not taking my eyes off his face.

He nodded, lips pressed together in a trembling line. "Oh, Nico," I murmured, and wrapped an arm around his shoulders, pulling him close.

"You're good at this," he mumbled thickly into my shoulder.

"At what? Talking to heartsick teenage boys? Sweetie, keep in mind I'm Percy's mom. You would not believe the amount of 'but how do I know if she's telling me she likes me or telling me I'm stupid' conversations we've had over the years."

"But isn't it different? I mean, I'm not your son, and I'm..."

I shook my head, looking him straight in the eye. "Nico, I know you're not my son, but you might as well be. You know you can treat this place like a second home whenever you like, and I will scold you if you run off and almost get yourself killed fighting monsters just as much as I would Percy. And as for having Will problems instead of Annabeth problems, frankly, I'm glad for the change. Okay?"

He nodded. "Sorry."

"Nico, stop apologising. I honestly don't mind. Now, what are we going to do about Will?"

Nico hesitated, glancing down at the floor. "I guess I could Iris-message him. Not now, he's not really a night person, and his siblings would kill me, but in the morning. That is, if I can stay here for the night?"

Was he really fifteen? He looked so much younger, hunched on my couch like a child who'd come in from the cold. "Of course," I said. "Do you want Percy's room? It's probably not too bad at the moment."

"The couch is fine," he said quietly. "Really, don't go to any trouble-"

"You look like you need a proper night's sleep," I said, ignoring the mutter about how this was his normal look, and went to find some spare bedding.

When I got back, Nico was taking off his shoes. His sword lay next to them, and I tried not to think about what sort of fifteen-year-old was fully dressed and carried a sword in the middle of the nights when they couldn't sleep.

"I've got some of Percy's pyjamas here," I said softly, setting them down on a chair. Nico nodded, taking the sheets from me and clumsily tugging them over the couch.

"Thank you," he said, slightly awkwardly. "Not just for the bed. I mean everything."

"It's fine. More than fine. Any time, Nico, understand?" I turned to go, when a hesitant voice called me back.

"Sally?"

"Yes?"

"You... you won't tell Percy about this, will you?" I could hear the drowsiness in Nico's voice already, seeping into his tone and making him sound younger than I'd heard in a while.

"No. Not if you don't want me to."

I heard the springs in the couch creak as Nico lay down. "Good," he murmured. "He'll only worry."

Without quite realising what I was doing, I crossed the room and gave Nico a gentle kiss on the forehead. He blinked up at me, dark eyes glinting in the half-light. Then he smiled. It suited him, in a aching kind of way.

"Goodnight, Nico," I said, and left the door open behind me, just a crack.