Yuuna and the Haunted Hot Springs Vol. 13

More about the book

There's a duel for 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...