Full Metal Panic! follows Sousuke Sagara, a young sergeant in Mithril, a covert anti-terror organization armed with advanced weapons and mecha, as he is sent to protect Kaname Chidori, a high school girl whose mysterious abilities draw the attention of hostile groups. That assignment quickly forces him into a battlefield he barely understands: ordinary civilian life.
Undercover at Kaname’s school, Sousuke tries to pass as a normal student, but his rigid military instincts and almost complete lack of social experience turn simple routines into constant chaos. Classrooms, trains, clubs, and daily errands become as perilous to him as any raid, while the enemies circling Kaname make clear that the danger around her is real. Across the franchise, the story moves between tactical combat, espionage, school comedy, and romance, showing how secrecy and trust can matter as much as firepower.
As Sousuke and Kaname grow closer, Mithril faces escalating conflicts and the line between duty and personal feeling becomes harder to keep intact. The result is a series that balances mecha action with character-driven humor and the uneasy bond at the center of the mission.