Riri enters Yurigaoka Girls' Academy to become a Lily and protect people from the Huge, but finds her fellow Lilies more competitive and combative than she'd imagined. When a Huge specimen escapes, can Riri survive her first battle with no training?

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 overjoyed that Yuyu is now her Schutzengel, but can she hold up under Yuyu's harsh training? Then, when a powerful Huge attacks, Riri gets a glimpse of Yuyu's secret.

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.

Yurigaoka holds a school-wide competition to choose the year's best Lily. Riri worries that the inexperienced Yuri could get hurt in the games, but with spies swarming outside the school grounds, that could be the least of her worries.

Riri is confined for a week as punishment for insubordination and sinks into depression over Yuri's death. The other members of her legion look for her missing hair tie, hoping to cheer her up, but will it be enough?

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.

The most powerful Huge yet is attacking Yurigaoka, and Riri is the only one left who can fight! Can Yuyu overcome her past in time to join her? And what can the other Lilies do against an enemy that disables their weapons?