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?

Yuyu wants to give Riri a birthday present but doesn't know what to give her. While Riri struggles to find two more members for her legion, can Yuyu overcome her awkwardness and find a way to cheer Riri up?

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?