There was a pattern: each person had lost something recently—an old photograph, a promise, the ability to remember the name of someone they loved. M4UHdcc did not announce that it would return these things. Instead, it stitched hints into public spaces: a QR code etched into a mural that, when scanned, replayed an old voicemail; a playlist uploaded to a forgotten streaming account that contained a half-forgotten favorite; an e-mail draft saved on a shared server that was the last unsent confession between siblings.