Nintama Rantarou: Dokutake Onsen no Dan

Synopsis

The lord of Maitake Castle asks for assistance, and the Headmaster of the Ninjutsu Academy decides to go with him on a secret visit to a dango shop. Students Rantarou, Kirimaru, and Shinbei also join them. When they arrive, it turns out the shop is a trap arranged by Dokutake Castle, and they become prisoners along with other captives.