What would it feel like to never forget? Or to have a memory stolen?

Seventeen-year-old Genesis Lee has never forgotten anything. As one of the Mementi—a small group of genetically enhanced humans—Gena remembers everything with the help of her Link bracelets, which preserve them perfectly. But Links can be stolen, and six people have already lost their lives to a memory thief, including Gena's best friend. Anyone could be next. That's why Gena is less than pleased to meet a strange but charming boy named Kalan who claims not only that they have met before, but also that Gena knows who the thief is.

The problem is that Gena doesn't remember Kalan, she doesn't remember seeing the thief, and she doesn't know why she's forgetting things—or how much else she might forget. As growing tensions between Mementi and ordinary humans drive the city of Havendale into chaos, Gena and Kalan team up to search for the thief. And as Gena loses more memories, they realize they have to solve the mystery fast…because Gena's life is unhappening around her.