Yuuna and the Haunted Hot Springs manga volume 13 features story and art by Tadahiro Miura.

There’s a free-for-all duel with a love potion on the line, and the whole Yuragi-sou crew are embroiled in a game of water gun survival! They’ll be pitting their strength and wits against one another to win the ultimate wet T-shirt battle royale. Meanwhile, Kogarashi undergoes some changes to his psychic powers which will require him to be even more hands-on with Yuuna than usual...