After a year in America, Kurisu Makise returns to Akihabara and reunites with Rintarou Okabe. However, their reunion is cut short when Okabe begins to experience recurring flashes of other timelines as the consequences of his time traveling start to manifest. These side effects eventually culminate in Okabe suddenly vanishing from the world, and only the startled Kurisu has any memory of his existence. In the midst of despair, Kurisu is faced with a truly arduous choice that will test both her duty as a scientist and her loyalty as a friend: follow Okabe's advice and stay away from traveling through time to avoid the potential consequences it may have on the world lines, or ignore it to rescue the person that she cherishes most. Regardless of her decision, the path she chooses is one that will affect the past, the present, and the future. [Written by MAL Rewrite]

Valkyrie, Kazuto, Akina, Hydra, and friends are back for more when the Key of time suddenly appears along with many other mysterious happenings. All seemed to be linked to a person named "Valkyrie Ghost" whose only goal is stealing Kazuto for herself. As they team up against this seeming unbeatable foe they dig deeper into the mysterious past of Valkyrie's home planet, Valhalla. (Source: ANN)

Unaired episode included in the seventh Blu-ray and DVD volumes. Haruka is busy working at the agency so she can't help the idols with the preparations for the Christmas Party held by Shining Agency. A lot of memories and information are revealed while Starish is preparing for the party.

The CH Postal Company has just received a request to transcribe a love letter from Irma Felice, a famous opera singer. Accepting the task, Violet Evergarden visits Irma to write her letter. However, not only does Irma provide little information, she asks Violet to write based on her own feelings. Despite Violet's numerous attempts, Irma finds every version of the letter inadequate. Violet consults her colleagues, and they help her out by writing love letters of their own. Yet even those are rejected by the opera singer. As a last resort, Violet asks Irma for her true thoughts and feelings, hoping to find the missing puzzle piece. Will the Auto Memory Doll be able to translate Irma's emotions into words? [Written by MAL Rewrite]