Out of male solidarity and… also for a compilation of 15 CDs, Thomas agrees to play Julia as Marc's girlfriend to dispel any illusions for Joséphine, the daughter of Marc's father's boss, who has organized a party. Marc's plan works wonderfully, even a little too well because Joséphine quickly takes refuge in her room. Julia, feeling guilty, discovers a girl who is really uncomfortable in her own skin, hyper aggressive. Using everything he has learned since he transformed into a girl, Thomas will try to restore Joséphine's confidence in both Julia and a boy. But Joséphine quickly falls in love with Thomas. How can he get out of this mess without hurting Joséphine? Thomas sees only one solution, make believe that Thomas is going out with Julia! Fortunately, thanks to this double betrayal, Joséphine will surpass herself and prove, during a bowling tournament organized by the gang for the rescue of Ursule, Nath's grandmother's tarantula, that she is worth much more than everyone believes.