The scientist André Delambre is obssesed by his latest invention, a teleportation device. When he decides to try to teleport himself, disaster strikes. During the teleportation, his atoms get mixed with the ones of a fly that got caught in the chamber with him. Now he has the head and left arm of a fly, and the fly has his miniature head and left arm. André's wife finds herself in front of a dilemma: save her man's life or kill the orrible monster?