Haruhiko embarks on a class trip to Hawaii with all the regulars of the series - Yuka, his buddies, and Yukanaria... and a new character: Haruhiko's former classmate Mana Kimura. Mana share's Haruhiko's love for fixing up gadgets, and also has a secret crush on him! What happens when Haruhiko gets involved with demons and magical weapons right in front of his friends...?