Private detective Ryo Saeba is hired to protect Ai Shindo, whose scientist father was recently killed in a suspicious traffic accident. Ryo has to stop a team of mercenaries, sent by young genius Shinji Mikuni, from getting to her. Shinji`s giant tech company is secretly working on military-grade attack drones which Ai`s father also helped create and now he needs Ai`s help to unlock her father`s creation.