Iroha decides to investigate Kamiahama City’s rumors in order to find clues about her missing sister, Ui. Mitama introduces Iroha to Tsuruno, the daughter of the owner of a Chinese restaurant called Banbanzai. Tsuruno asks someone who is familiar with the rumors to help investigate, but Yachiyo is the one who shows up at the meeting spot. Tsuruno says Yachiyo is knowledgeable about the rumors of Kamihama City. The three suspect that the Séance Shrine may have something to do with Ui’s disappearance…

Iroha moves into Mikazuki Villa and transfers to Kamihama City University Affiliated School. She discovers that even though Kaede goes to the same school, she is unable to contact her. Iroha has a hard time getting used to her new surroundings, so when she sees that Rena doesn't have many friends in class, they decide to eat lunch together on the rooftop. Iroha is still gathering information about various rumors, and Rena tells her about the rumor of the Invisible Girl and Endless Solitude. Tsuruno hears about the rumor of the Radio Wave Girl from a regular at Banbanzai and tells Iroha about it.

Iroha refuses to join the Magius. When she and Yachiyo meet up, she is eager to go search for Tsuruno and the other girls. However, Yachiyo believes that her wish brings tragedy to those around her and tells Iroha that she is disbanding the team. The Memory Museum begins to collapse. Iroha and Yachiyo try to escape, but Mami, who has become an entirely different person, attacks them.

Iroha hears about Nemu Hiiragi, the best friend of Iroha’s younger sister, Ui, from Kuroe. Iroha finds out that Nemu, who is also a member of the Magius, remembers her and asks Kuroe to take her to Nemu so they can talk. Iroha, Yachiyo, and Kuroe head to Hotel Fendt Hope, the headquarters of the Magius. When the trio arrive at Hotel Fendt Hope, they have an encounter with the Amane sisters. While Yachiyo distracts the Amane sisters, Iroha and Kuroe make their way into Hotel Fendt Hope to find Nemu, but they bump into Rena Minami and Kaede Akino, who are dressed as the Black Feathers.

Iroha embarks on a journey to find her friends from Mikazuki Villa. Kuroe is genuinely concerned about Iroha so she decides to tag along. Meanwhile, Felicia and Sana are working inside of the Magius as Black Feathers. Felicia proclaims that she will not return to Mikazuki Villa until she finds out how they can avoid becoming witches. Sana begins to question the actions of the Magius while she manages the people captured by the Uwasa,. Mifuyu, who is acting as a White Feather, finds herself in a predicament when she reunites with an unexpected person. Amidst the intricate tangle of everyone’s emotions, Touka announces her strategy to save all Magical Girls. What could it be?

Tsuruno, who had merged with the Uwasa, is defeated, which triggers Touka from the Magius to direct her rage toward Iroha and her friends. Touka sends the Uwasa of the Soldier Bear army to attack them. Nemu is upset with Touka’s actions and at how things aren’t turning out the way she intended. Meanwhile, Iroha finds herself alone in a strange world. She is sitting in a seat in a theater where a Magical Girl named Mel is predicting the future. When Iroha sees Mel, she remembers the past events that Touka showed her at the Memory Museum.

It happened in the past… Iroha would go to the hospital daily and play with Ui, Touka and Nemu. The girls loved Iroha and looked forward to her visits. One day, the three girls create an Uwasa similar to an urban legend while playing. That way, if they died, the Uwasa they created would live on and remind Iroha of them. Iroha also created the “Uwasa of Eternal Sakura”, with the wish that the three girls will be discharged from the hospital without illness. And one day... Kyubey appears before Iroha.

The Magical Girls rush to Iroha while fighting against Uwasa of the Soldier Bear. The Amane sisters also stand in their way, but Mifuyu keeps them in check. "The plans of the Magius have failed." Meanwhile, Iroha and Touka regain the memories that Nemu's power took from them. Touka is happy to be reunited with Iroha but can’t recall why they became enemies in the first place. Nemu tells Touka why she had been hiding the truth until now. Now, they see the promise they made with Ui in a new light.

To fulfill their promise to Ui, Touka and Nemu set their plan in motion with Embryo Eve. Yachiyo desperately tries to stop them. As Alina watches events unfold, Kuroe is isolated and alone. And Kyubey is not far behind… Meanwhile, Iroha wakes up in her room at home. Everything looks the same as when Ui was still around. Finally, Iroha is reunited with Ui.