"Starting on All Fools Day, twelve years ago, I remember everything. EVERYTHING. That was a wet Saturday, and that was the day I was born." 12-year-old Piaf has the ability to (and burden of) remembering everything that has happened since the day she was born. When she discovers everyone in Paris has forgotten the entire last year, 1887, including the disappearance of several gifted children, Piaf and her twin brother Luc embark on a dangerous journey that brings them to the depths of Paris's underground twin, the Catacombs, to capture the memory thief and find the lost children.