Senran Kagura: Ninja Flash

Asuka, Ikaruga, Katsuragi, Yagyu and Hibari are five school girls who secretly train in the ninja arts. As they are sent by their mentor, Kiriya, to handle some delinquents in town, Asuka meets a girl named Homura and helps guide her through town, unaware that she is secretly an enemy shinobi. Meanwhile, the others encounter the delinquents, who are soon revealed to be wooden puppets controlled by an enemy shinobi. As the girls manage to beat the puppets, Asuka remains blissfully unaware of Homura's true alliance.

As the girls train in summoning animal spirits, Asuka is the only one having trouble summoning hers. Her grandfather, the legendary shinobi Hanzou, comes to visit and informs her that their family's spirit is the tree frog, which Asuka is afraid of. As Asuka attempts to get used to frogs, Hanzou informs Kiriya that the evil Serpent Academy for Girls is behind the puppet attack. On their way home, Asuka and Ikaruga are attacked by one of the enemy shinobi, Yomi.

Yomi engages Ikaruga in battle and overwhelms her with her array of weapons before taking her leave. Later, Ikaruga is informed that her brother, Murasame, who she replaced to become the shinobi successor of her family, has gone missing. Later that night, Ikaruga encounters Murasame in her room stealing her sword, Hien, but she manages to send him packing easily enough. After being ejected from the household, Murasame is met by Hanzou, who reminds him that being a shinobi isn't the only way of life. After receiving some advice from Hanzou, Ikaruga decides to start giving Asuka summoning lessons, managing to help her get over her fear of frogs and learn to use her summoning art.

Kiriya takes the girls to Shinobi Island to train. Two more dark shinobis, Mirai and Hikage, attack. As with the other battles, neither Mirai nor Hikage took their battles seriously and left rather abruptly. However, Mirai revealed to Hibari that she is a freshman at the Serpent Academy for Girls, leading Kiriya to inform his students that these dark shinobis are also from that same academy.

The dark shinobis from the Serpent Academy receive new orders to make an attack on Hanzou Academy. Haruka, the puppeteer, sets up puppets to distract Asuka and the others while a linked barrier is set up to separate the group and force them into their own battles. Asuka finally finds out that Homura is a dark shinobi from the Serpent Academy and is forced into battle. Yagyuu is set up against Mirai, Hibari is set up against Haruka, Katsuragi gets a rematch against Hikage, and Ikaruga is forced to battle against Yomi. This time, the dark shinobis appear to be taking things more seriously. The instructor of these 5 dark shinobis, Suzune, speaks with a mysterious voice about obtaining a scroll known as "Yang" from Hanzou Academy. The Serpent Academy holds a scroll known as "Yin", but their goal is to obtain the "Yang" scroll from Hanzou Academy.

The battles from the last episode continue. Mirai loses her battle against Yagyuu, causing the Linked Shinobi Barrier to become weaker and the dark shinobis to retreat. Despite the Hanzou Academy students putting up a better fight, Yagyuu was the only one that won her fight. Yagyuu was injured trying to save Hibari, but recovered quickly. It is revealed that Yagyuu looks after Hibari because Yagyuu sees a lot of her late sister in Hibari. Hanzou returns to the Academy to discuss the situation with Kiriya and informs him that "it is time to find a successor to the super secret ninja arts". The scroll that contains these arts chooses its owner. Who will it be?

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.

The Shinobi Masters tournament has begun, but is Naked Dodgeball really the best way to determine the ultimate shinobi?!

The tournament to decide the ultimate Shinobi Master continues.