Nico di Angelo slipped out of Camp Half-Blood before dawn, when the world was still quiet enough to pretend it wouldn’t notice him leaving.

January air clung cold and sharp against his skin, frost crunching beneath his boots as he crossed the empty clearing. The cabins were dark, the lake still, even the harpies asleep. It was easier that way. No questions. No looks. No one noticing the date.

January 28th.

Birthdays were… complicated. They always had been. Too many memories tied to things he’d lost—Italy, his mother, Bianca. Celebration felt wrong, like tempting fate or reopening wounds he’d learned to keep sealed. The Underworld, at least, was honest. It didn’t expect smiles or candles or wishes.

Nico stepped into the shadows and vanished.

By the time Will noticed Nico was gone, the sun was already creeping over the treetops.

He noticed because Nico always left a note when he went somewhere dangerous. Or a half-muttered warning. Or at least a shadow lingering a little longer than usual.

This time, there was nothing.

Will stood in front of the Hades cabin, heart ticking faster with every second. Nico’s bed was empty. The shadows were restless. And something—some instinct Will trusted more than logic—told him this wasn’t just another solo trip.

He went straight to Annabeth.

“January twenty-eighth,” she said slowly after checking a notebook she absolutely did not need. Her eyes widened. “That’s Nico’s birthday.”

Will froze. “…What?”

“He never tells anyone,” Percy added from behind her, arms crossed. “But yeah. Bianca mentioned it once. A long time ago.”

Will felt something twist in his chest—hurt, yes, but more than that, understanding. Of course Nico would leave. Of course he’d disappear into the one place that made sense to him instead of staying to be seen.

“Okay,” Will said, straightening. His voice was calm, but his eyes were bright with resolve. “We’re not letting him spend it alone.”

By midday, Camp Half-Blood was quietly mobilized.

Percy handled decorations—badly, but enthusiastically. Annabeth organized. Grover supplied snacks that were safe for everyone. The Apollo cabin handled cake (with strict instructions: no chamomile anywhere near it). Will hovered through all of it, heart buzzing with nerves and hope, replaying every moment he wished he’d asked Nico more questions.

By evening, everything was ready.

Nico returned just after sunset.

The Underworld had been quiet, as it always was for him. Hades hadn’t asked questions. Nico hadn’t offered explanations. He stayed just long enough to feel grounded, just long enough to convince himself this was what he wanted.

When he shadow-traveled back to camp, exhaustion tugged at him—but so did familiarity. He walked up the hill toward his cabin, hands in his pockets, already planning to collapse into bed and let the day end quietly.

He opened the door.

“HAPPY BIRTHDAY!”

The lights flicked on. Streamers fell from the ceiling. A crooked banner hung over the fireplace. Percy nearly tripped over a chair. Annabeth smiled softly. Grover bleated in excitement.

And Will stood at the front of it all, holding a small cake, eyes locked on Nico like the rest of the world had gone silent.