In a Parisian laboratory, a severed hand escapes its unhappy fate and sets out to reconnect with its body. During a hair-raising escapade across the city, the extremity fends off pigeons and rats alike to reunite with pizza boy Naoufel. Its memories of Naoufel and his love for librarian Gabrielle may provide answers about what caused the hand's separation, and a poetic backdrop for a possible reunion between the three. Based on Guillaume Laurant's novel "Happy Hand."