At the Séance Shrine, Iroha wrote her sister's name, Ui, and Yachiyo wrote the name of her former best friend, Mifuyu, on votive plaques. As if to confirm the truth of the rumor, Ui and Mifuyu appear, but they are twisted imposters of their loved ones. Iroha and Yachiyo are attacked by the fake Mifuyu and the master of the Séance Shrine, a Horse Monster, and find themselves in a bind that threatens to end their lives. Iroha's Soul Gem gets cloudy, making her slowly lose consciousness. What sort of transformation will she undergo?

With Yachiyo in low spirits, Iroha and company leave her behind and head for the Memory Museum. Touka Satomi, a friend of Iroha’s sister, Ui, awaits them there to give them a lecture about the truth of Magical Girls. Yachiyo’s past memories give her a push, and she decides to go find Iroha. However, at that very moment Iroha is already in the midst of a "vicarious practical learning" course prepared by the Magius.

Yachiyo and Kuroe find Iroha inside the Labyrinth of the Uwasa of the Eternal Sakura. However, Yachiyo and Kuroe are swallowed by the Doppel of Silence that suddenly appears from Iroha’s body. When Yachiyo awakens, she finds herself at Mikazuki Villa eating breakfast with Tsuruno, Felicia, Sana, and Iroha, but Kuroe, who is not supposed to be there, is in the room with them. Yachiyo and Kuroe are baffled by the situation they are in, but they have a hunch that they are not in the real world, but in a dream world being shown to them by the Doppel of Silence. They are concerned about Iroha’s safety in the real world, so they do all they can to wake up Iroha in the dream.

Kuroe lets Iroha get ahead of her while fighting with Magius. Kuroe hears a whisper that puts her in a shock: “Did you forget about me?” At the same time, Iroha is hearing Ui’s voice. Felicia and Sana are confused about Magius’ plan. Sana has questions and explains her intent to Mifuyu, who seems to have given up on everything. Due to the plan, Yachiyo is after Iroha in Kamihama City, which is filled with a large number of Witches. While there, Yachiyo comes across a Magical Girl from Mitakihara City.

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.

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.