In the wake of the Ryunka disaster, Tokyo is plunged into a period of social unrest. To compound the problem, the aliens directly responsible for the catastrophe have escaped from the Space Federation and are currently hiding on Earth. Birdy Cephon Altera, a Space Federation officer, and Tsutomu Senkawa, a high school student, still share a body. They are tasked with capturing the fugitives and bringing them to justice. However, an unexpected crisis arises when the outlaws become targets of an unknown assassin driven by a vendetta. Now, Birdy must navigate the chaos of everyday life while uncovering the assassin's identity before more escapees fall victim.