On the Mishmash of hams" cycloid, child Cothrom sees his mother being killed by an unknown alien while his nanny drone rescues him. Become a savage, an AI finds him and sends him to a school where he rubs shoulders with extraterrestrials.
At seventeen, the boy must leave with a friend Beliaire to become a detective Effector on the planet Tapehii by first stopping off amongst the Amazons of TchikiBoum. After graduation, they set out to find the missing daughter of a major builder.
In this quest where many dangers already threaten them, the vampire monster tracks the young man to kill him, but Cothrom intends to avenge his mother. However, the unpredictable gets mixed up in the situation.