

Ickis, Krumm and Oblina are bored. Oblina has the bright idea to organise a slumber party. Girl monsters only. Ickis, Krumm and their friends, with nothing better to do, decide to sabotage the girls' night.
The festival celebrates the shedding of skins that each monster must undergo as he or she moves from childhood to adolescence. As the festival approaches, Krumm is chosen to form a band and Oblina is chosen to perform the festival's ceremonial dance. Ickis, who shows no signs of shedding, feels left out.
Ickis, Krumm, and Oblina sneak into Simon's house to scare him. After the scare, Simon seems to know the monsters' whereabouts. He shows up when they least expect it. How is he doing it?