Sonoa gets drunk and ends up living at Tachibanakan. Yuu gets everyone to have a welcome party for Sonoa, so they meet by the riverside in appropriate outfits. Yuu has water guns waiting for them, and has everyone enter a "Water Gun Survival Game".
Why do I have to get caught up in this?!
Warum wurde ich da hineingezogen?!
¡Me tendiste una trampa!
¡Me tendiste una trampa!
Perché sono finita
 a fare una cosa del genere?!
Por que eu tive que entrar nisso?!