Naïve 16-year-old Mamori Tokonome is accustomed to being teased at school for having an unfortunate surname that can also be read as "virgin." However, young Mamori will soon have to get used to being teased in other ways... Kidnapped during gym class, Mamori wakes up only to find herself stranded and under attack on the exotic island of Mermaid. Luckily, enigmatic fellow castaway Mirei Shikishima knows exactly how to take the lead—through a passionate kiss, Mirei unleashes Mamori's Exter transformation abilities, turning the innocent red-head into a battle-ready cutlass through the power of arousal. The duo will need to tap into that power as Mermaid Island is full of potential friends and foes: Charlotte, the sadistic Liberator of an Exter harem; the gluttonous and crafty Meifon; the mysterious but charismatic Akira Hiiragi; and the erotic biker duo Lady Lady. Mamori and Mirei's powerful and intimate embrace is the only way for the pair to ensure their survival on this scandalous island. [Written by MAL Rewrite]

Rikuo Uozumi has all but resigned himself to a bleak future, aimlessly working at a convenience store in Tokyo after graduating from college. His monotonous life is interrupted when the peculiar Haru Nonaka makes a lively appearance, frequently dropping by his workplace to befriend him. When Rikuo learns that an old college friend and crush, Shinako Morinome, has moved back into town, he reaches out to further their relationship. Unbeknownst to Rikuo however, Shinako is carrying painful memories from her past that were holding her back from accepting his feelings. Meanwhile, as Haru continually opens up to Rikuo, he discovers that she, much like him, is living by herself and wants to step out of her comfort zone into an uncertain future. The past lingers long in the mind, and the future remains elusive. At a crossroads along their intertwined paths, these three experience what it means to let go of their feelings of yesterday and embrace the change that tomorrow brings.

Mini OVA episodes bundled with the Blu-ray and DVD releases of Valkyrie Drive: Mermaid.

Kiss kiss, bang bang! The arms race takes on a startling new development when the arms come with heads, legs and very feminine bodies attached! Yes, at Seishou Academy every girl is literally a lethal weapon, and they're all gunning for the top shot at getting their own personal serviceman! Needless to say, it's going to be difficult for newly recruited human instructor Genkoku to adjust to working with a living arsenal of high caliber cuties with tricky names like FNC (Funko) M 16A4 (Ichiroku) L85A1 (Eru) and SG 550 (Shigu). Especially since many have hair triggers and there's no bulletproof vest that can stop a really determined coed! He'll have to rewrite the operator's manual on student/teacher relationships, and pray that his job description won't include having to field strip and reassemble one of his cadets in the dark. But unfortunately (for him) FNC's already thinking about becoming HIS personal weapon, and she usually gets what she aims for! (Source: Sentai Filmworks)