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, she must fight 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 is overjoyed that Yuyu is now her Schutzengel, but she may not be able to hold up under Yuyu's harsh training; when a powerful Huge attacks, Riri gets a glimpse of Yuyu's secret.

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.

Yuyu wants to give Riri a birthday present but doesn't know what to give her; Riri struggles to find two more members for her legion.

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.