S1, E5: Yaiba and team head to the infamous Ganryu Island to learn more about the enigmatic weapon known as the Monohoshizao, a maken once wielded by Musashi's one-and-only rival, Kojiro Sasaki. But one of Onimaru's minions, Mr. Slug, has other plans. Eager for an escape, Yaiba and his entourage pay a visit to the restorative hot spring Gero Onsen. Instead of finding relaxation, however, Yaiba and friends are ambushed by, of all people, a local hotel employee who claims they've just won an exclusive, all-paid stay at his luxurious hot spring resort. Yaiba couldn't be more excited, but someone - or something - is waiting...