Emile is a contract killer. A hired killer who travels by bicycle and who kills in exchange for a few tickets left in a small mailbox lost in the middle of the fields. This time, the man to be slaughtered is named Gaston Pouget and lives at 7 rue des Peupliers, which is a shed on the edge of a highway. Only here, when arriving on the scene, Emile is surprised by a birthday in honor of Gaston who should arrive soon. Emile was not invited.

Lucille, an introverted eleven year old girl, live with her parents, who are caretakers of the swimming pool in which they stay. Because of the weirdness of this place, which looks like a flying saucer, an awful anguish comes out of Lucille's mind. The "unidentified frightening object" of her confusion would happen to be even more obsessing than all fears of childhood.