Valkyrie Drive: Mermaid - Season 1 - Eps 7: To Believe
Stressed from work, Akira, who is revealed to be a woman, sneaks out to be spend some time with Torino, keeping her identity a secret from Mamori and Mirei. Spending the night in Mamori's room, she recalls how her mother arranged for her to act like a man upon arriving at Mermaid in order to stay safe. The next day, some rebellious girls take one of the Ritters hostage in the building where Akira is keeping her male clothes. As Charlotte and Kasumi argue over how to approach the situation, Mamori, Mirei, and Akira follow a secret passage into the building in order to rescue the hostage, only to fall into a trap laid out by the Ritter, who was sick of her current life. With Mirei knocked out, Mamori has Akira drive with her in order to stop the terrorists, briefly exposing her identity to Mirei before leaving the scene.
About Valkyrie Drive: Mermaid

Title: Valkyrie Drive: Mermaid
First Air Date: 2015-10-10
Last Air Date: 2015-12-26
Status: Ended
Rating: 7.1/10 (from 35 votes)
Language: JA
Seasons: 2
Total Episodes: 12
Network: AT-X Tokyo MX Sun TV TV Aichi BS11 KBS Kyoto
Genres: Animation, Action & Adventure
Production Companies: ARMS
Synopsis
Tokonome Mamori is transferred to Mermaid - an artificial quarantine island for people with superpowers. When Mamori is attacked, a newly transferred girl named Mirei saves her. The enemy doesn't stop, however, and the two are soon cornered. Just when they think all hope is lost, Mirei kisses Mamori, and Mamori turns into a sword. Mirei then wields the sword and launches a counterattack against their enemies.
Cast

Yuka Iguchi
Mirei Shikishima

Mikako Izawa
Mamori Tokonome

Yuna Yoshino
Akira Hiiragi

Asami Seto
Charlotte Scherzen

Azumi Asakura
Lady J

Masumi Tazawa
Kasumi Shigure

Yurika Kubo
Meifon Sakura

Hitomi Harada
Momoka Sagara

Saori Onishi
Rein Hasumi

Kikuko Inoue
Torino Kazami