after the school festival, everyone in the investigation team went to the Amagi inn with Nanako. The guys are in their separate room, which has an... Eerie feel. The phone rings, scaring everyone. Kanji picks it up with a shaky hand tells everyone that the hot springs are empty right now

You walk outside as Teddie cannonballs into the hot springs... Where the girls are. It'll be a long night Yosuke: what the hell are you doing here?! Chie: I should be asking you that! In an instant, the calm hot springs were filled with, screams, and wooden barrels being thrown by the girls Yosuke: hey, what the hell do we do?! Yu: the situation is dire... Kanji: yeah, no shit.