By morning, it had a million plays. And a new comment, from an account that shouldn’t have existed:

She looked up the username attached to the folder. Last active: 407 days ago.

Inside: a recording. Not her voice. A young man, out of tune but desperate, singing a verse she’d never heard. The lyrics were about a subway station, a missed call, a winter coat left on a train.

“Who’s there?” she typed into her private notes.