A sentence begins to spread: You are not your thoughts; you are what survives them. It comforts some people. It hollows others. There is no lab leak, no implant — only language, and the ordinary hunger for relief.

When a cognitive scientist who studies contagious ideas realizes the phrase may have grown from her own abandoned work — and may now live in her daughter — the question turns personal: if a thought can colonize a mind, what remains of the person who loved them?

A literary novel of obsession, identity, and the ideas we cannot stop carrying.