An enigmatic android plummets from the sky and crashes into Shinichirou's quiet cafe, immediately registering him as her new master. Though household chores prove far from her strengths, Arisa gradually settles into the daily rhythm alongside his sister Kotomi. When an unfamiliar girl arrives seeking the mysterious Fire Bee, long-buried secrets tied to Shinichirou's missing father begin to emerge, placing everyone in sudden danger from relentless military pursuers.