In two days, it's the "En avant la Sic-Mu" festival! Thomas brings everyone into the adventure. Writing the lyrics, composing the music, rehearsing, it's a total blast between the girls and the boys. Until Marc and Laurent bring back Nath and Aude's stage costumes. Mini-skirts and ultra-low-cut tops! It's a clash. Out of the question for the girls to play the "Barbie-potiches"! Since that's how it is, they'll both sing. The war of the sexes has been declared! Even Thomas can't stop it and has to run from one group to another.