WARNING: The following contains spoilers for Mars Red Episode 7, "The Letter," now streaming on Funimation.
Mars Red's Episode 7 is a flashback, set a year before the start of the series. The story finally focuses on Misaki Nakajima, the actress-turned-vampire who had deep connections with Nakajima, Maeda and Deffrott and who died in the very first episode.
Episode 7 follows Misaki during her months as the leading actress in the Imperial Theater. She forges a friendship with Deffrott, the lonely child actor/elder vampire living and working in the same theater. After a few false starts, they become friends: she offers him warmth, companionship and kindness and he coaches her to become the best actress of the Imperial theater.
However, it all comes tumbling down when Misaki goes home to visit her father, General Nakajima, and to pick up the letters from her fiancé, Maeda. She had planned to spend the night on her family's estate and write a letter to Maeda, but instead she overhears a conversation between her dad and a mysterious hooded man.
This man is none other than Rufus Glenn, the Scottish vampire who had been developing Ascra, the artificial blood source that turned humans into vampires without killing them. Nakajima wanted that blood to create his vampire squadron, but there had been a few false starts. Glenn gives Nakajima a vial of S-blood from Yokohama (one of the outbreak spots later in the series) and admits that he had to "make some sacrifices," to which Nakajima shrugs. Unfortunately for Misaki, Glenn senses her presence -- and Glenn doesn't like to leave witnesses.
Misaki heads back to the theater feeling conflicted and, more importantly, suspecting that vampires might actually exist. She's so troubled that Deffrott notices immediately. Misaki almost confesses everything to Deffrott, asking whether he believes that vampires exist. Deffrott, a vampire himself, doesn't know how to answer, but before he can think of something Misaki changes into her Salomé costume and goes to rehearse.
It's the best monologue of her life, and unfortunately the last -- the heavy columns of the stage come tumbling down, crushing her, and it's heavily hinted that this was Glenn's doing. Deffrott snaps, feeding Misaki his blood so that she lives to "show her Salomé to Maeda." Unfortunately, Nakajima finds out about his daughter's new condition and locks her up in the underwater prison where Maeda found her at the beginning of the season.
The episode, which had begun with an angry Deffrott standing over an almost dead Maeda, ends with Deffrott scolding him for daring to die when he has to fix all the things that his dumb military broke. The Great Kanto earthquake that shook Tokyo in the previous episode, collapsing Code Zero's headquarters, had also put a metal beam through Maeda's torso, so he's basically done for.
Defrott, however, won't allow this. He misses Misaki, hates her father for locking her up and holds Maeda responsible for the promises he made to her. Deffrott also knows that Rufus Glenn is in the city, he has a vial of Ascra in his possession and is concerned about the intentions of the other British vampires, who actually wanted to enslave the whole of Japan and were using Nakajima as a tool to accomplish that goal.
Deffrott is pissed at the absurd situation, so he lifts his wrist, like he did as Misaki was dying, to grant Maeda the gift of vampirism so that he survives and stops Nakajima's deranged plan. This is ironic, because Nakajima really wanted Maeda to become a vampire so that he could lead his vampire troops on the battlefield, and Maeda's vampire friend, Yamagami, sacrificed himself to keep him human and alive.
