The first volume in the third series of Full Metal Panic.

To Souske Sagara, undercover high school student and member of the mercenary group Mithril, life in Tokyo seemed the same as always. But underneath the promising exterior spin the wheels of a conspiracy that threaten to destroy the peace. Unrelated at first glance, a series of tactical assigments draws Mithril's Special Reponse Team into a tangled web, with the spider wearing a haunting face from the past! With inside help and technology to rival their own, this adversary is after the Arbalest no matter the cost. And don't forget that math test...