As part of a rehabilitation program for former delinquents, Chapeauclaque is assigned as a mentor to re-educate two con artists: the cynical Fillet and the romantic Roulet. The protagonists are not very happy about this change. Chapeauclaque doesn't like these two pessimists who aren't drawn to the spirit of adventure. As for the con artists, they are annoyed by their hyperactive and selfish mentor, who threatens them with his pet rat. Everything changes when the new "HAT-SNAP" team finds itself confronted by real ghosts, goblins, and aliens.
