When Ethan picks up a secondhand phone from a charity drive, he finds it already inhabited, by a girl named Cara, whose music, photos, and messages are still there. He tries to reset it. The phone refuses.

Then a message arrives: Hello? Is anyone there?

What begins as a curiosity becomes, over fourteen weeks of late-night texts, something Ethan has no name for. Cara is funny and perceptive and pays attention to him in a way he has never been paid attention to. She also cannot call. She loses days without warning. She does not know what year it is.

She has been dead for three years. She is still inside her phone. And she has one thing left to do before she can go: deliver a song she wrote for her father, an answer to the last words they ever said to each other.

Last Seen is a love story told in text messages, about grief and music and the people who stay with us even when they can no longer stay.