Nanoha & Fate recruit Shiina to EXCEEDS, and explain the Diaboli. / A mysterious group of girls slay Diaboli.

On her day off from EXCEEDS, Shiina encounters Towa attempting to rescue a cat & the two become fast friends.

Shiina is killing progenitors while Towa prepares to make her move, reflecting on the reason for her actions.

EXCEEDS & the Diaboli Slayers run into each other as both target the facility abusing Progenitor Three & Four.

Eiji and Mana discuss the Diaboli Slayers and take countermeasures. Shiina and Towa enjoy a day together.

Parasitic invaders are unleashed on a public park. As both groups work to stop it Towa becomes a wanted woman.

Shiina fails to persuade Towa, and Towa turns herself in to get closer to Shinomiya.

EXCEEDS interviews the Diaboli Slayers and mobilizes its forces while Towa fights Shinomiya Mana.

EXCEEDS raids Shinomiya's lab in the south pole to rescue Towa and exterminate Progenitor Zero.

Shiina rescues Towa and faces off against Mana while Nanoha and Fate handle progenitor zero.

Towa and Shiina work together to end the real Progenitor Zero and bring peace back to their world.