Bizarre creatures referred to as Unknown appear over the coast of Tokyo Bay and must be repelled by high school students in Tokyo, Kanagawa, and Chiba.

Suzaku is teamed up with Hotaru and one of his least favourite people, Kasumi, to investigate rumours of an Unknown appearance.

Ichiya skips patrol duty to visit a student in the hospital, and a colossal new type of Unknown appears in his absence.

After being saved by the Chiba and Kanagawa forces and beating a retreat, Suzaku is called to take responsibility for acting on his own.

The casualties caused by the Unknown's sudden attack are so severe that Suzaku loses his confidence and will to fight, so Maihime steps up to act as Tokyo's leader.

Hotaru engages in combat with a new type of Unknown in the no-entry zone and Suzaku fights a desperate battle at Umihotaru.