On Earth in the near future, humanity faced imminent destruction from mysterious giant creatures known as "Huge." The entire world unites against the Huge, and successfully develops weaponry known as "CHARM" (Counter Huge Arms) by combining science and magic. CHARM exhibits high rates of synchronization with teenaged girls, and the girls who use CHARM are viewed as heroes called "Lilies." Throughout the world, "Garden" military academies are established to train Lilies to face the Huge and to serve as bases to protect and guide people. Riri Hitotsuyanagi managed to pass the exam to enter the prestigious Garden known as Yurigaoka Girls' School. She entered in an attempt to find Yuyu Shirai, a girl who rescued her in her past. This is a story about Riri and other girls who aim to become Lilies at one such Garden.
Tokonome Mamori is transferred to Mermaid - an artificial quarantine island for people with superpowers. When Mamori is attacked, a newly transferred girl named Mirei saves her. The enemy doesn't stop, however, and the two are soon cornered. Just when they think all hope is lost, Mirei kisses Mamori, and Mamori turns into a sword. Mirei then wields the sword and launches a counterattack against their enemies.
While Rena and Maki recover from their injuries, the other SORD members jet off overseas for a school trip. Within moments of their arrival, though, the Mihama gang are pulled into a manhunt for a SORD deserter, assisted by student Sylvia and Velvet of St. Aile's International School. Tohka's the star of the show this time round, but she's wrestling with her own issues - old memories of her parents, and a promise to a friend that she wasn't able to keep...
