Riri is determined to get Yuyu to agree to be her Schutzengel and find out what changed her, but Yuyu won't even talk to her. Riri works out her feelings as she learns her way around Yurigaoka Academy.

Riri is slacking off now that Yuyu has accepted her. Yuyu asks Riri to form a legion to keep her active, expecting her to fail. But when Riri starts actually recruiting members, Yuyu may be in for more than she bargained for.

Riri's newly formed legion goes to watch an experienced legion fight to study teamwork. The Huge they're fighting, however, is more than it seems, and Riri and Yuyu's bond will be tested like never before.

Riri finds a mysterious girl in the remains of a dead Huge. The amnesiac girl quickly grows attached to Riri, who devotes herself to taking care of her. But just who is this girl, and how will Riri's legion deal with her absence?

When Yuri's origins are revealed, she is classified as a Huge. Riri flees the academy with her, but orders are issued for their capture. What will the other Lilies choose when ordered to hunt one of their own?

As Riri and the others continue to grieve, Yuyu isolates herself, tormented by visions of Misuzu. As the Huge attack Yurigaoka as they never have before, Yuyu is forced to question the truth of her relationship to her late Schutzengel.