The Berith Onsen was located near a flow of lava proximate to hell, making it an excellent place for hot Springs, a luxury Japanese-theme hostel was build and apparently was quite popular.
In their way to find the Cross-Eyes hideout, Nikaido, Kaiman and Natsuki spend a night in the Onsen to rest and start their search in the morning. Natsuki was hoping to find the top officers and make them pay their expenses, in a twist, Ushishimada, Ton, Tetsujo, Saji and Dokuga were working in the hostel to earn some money as kitchen helpers and delivery.
En found out the scam of Asu when Chota was reverted to his original body (posing as Nikaido to keep En busy while she and Kaiman escaped). Infuriated, he chased them to the onsen where he and Kaiman had their final fight, the sorcerer killed the lizard head seeding the air with mushrooms spores and making them burst through his chest, but before that, and while Ebisu's magic was dispelled, giving Kaiman his original face, he was able to break En's face with a single punch, this made the sorcerer to completely lose it and wrecked the whole building with his magic, nothing stood there except giants mushrooms. Nikaido was kidnaped once again by En, Asu took the person he believed was Kaiman and teleported as far as he could, the Cross-Eyes and Natsuki escaped to their hideout and nobody paid their bills in the end.