Just as she's about to leave on vacation, Agathe is asked to take Clément, her ex-husband's son,
with her on the road to Auvergne, where his mother is waiting for him. Along the way, the two
pick up a hitch-hiker named Zerph. Zerph turns out to be an extraterrestrial who is being chased
by two indestructible enemy robots. Clément and Agathe sympathize with him and try to help.