Asuka and Yumi run into each other while doing their Christmas shopping and spend some time together, talking about how they balance their lives as both high school girls and shinobi. While Yumi searches for a present that Asuka dropped, the other Hanzo girls are suddenly attacked by two girls named Gekkou and Senkou, who then proceed to attack Asuka, completely overpowering her.

Unaware of what happened to Asuka, Yumi and her Gessen squad receive a message inviting them to a spa resort. Meanwhile, Homura's Crimson squad come up against Miyabi and her Hebijo squad during a mission, during which both teams receive the same invitations. Accepting the invitations, the three squads go to the resort together and have a water gun fight in which they aim to make their opponents' swimsuits transparent, which ultimately ends in a tie. The girls are then confronted by Gekkou and Senkou, who announce that they are holding the Hanzo girls as hostages to force everyone to take part in a Shinobi Masters tournament. Afterwards, Yumi comes across Asuka, the only one not captured by the pair, whose sense of justice has been shattered by her defeat.

Following a heated conflict with Asuka, Yumi comes across Homura, who invites her to a hot spring to heal up her injuries. Meanwhile, youma hunter Kagura is approached by a mysterious woman named Fubuki, who invites her to the tournament to face off against the ultimate youma. Back at the spring, Homura is confronted by Asuka, who uses underhanded means in order to defeat her and keep her out of the tournament.

Learning that Gekkou and Senkou are students of Gessen Middle School, Yumi and her team infiltrate the middle school to investigate. The girls soon come up against the pair, who state they intend to follow the teachings of Yumi's grandfather, Kurokage. After Asuka sneaks into the location the night before, the Shinobi Masters tournament begins.