The whole group goes camping on a day off. Nyarko grills some suspicious meat on the BBQ and Mahiro won't eat it. Nyarko's friend, Atko, had sent them some chocolates, but Mahiro won't eat that, either. As they wander the forest, they find an old mansion. They attempt to explore it, but a rather unexpected surprise awaited them...
I'm sure the punchline is just that 
there are mice in the walls.
¿Y no será que hay ratones 
dentro de las paredes?
¿Y no será que hay ratones dentro de las paredes?
Tenho certeza que são só ratos nas paredes.