Asako Kusakabe rescues a young Yuuji from terrorists on a certain mission. She has evaded death as a soldier time and time again, and on a whim decides to become Yuuji's guardian. Although she partially forces it, and despite her coworker JB's concerns, the awkward female soldier and young man begin to live under the same roof.

Yuuji goes to America to follow the same path as Asako, and through his rigorous military life meets and forms a deep bond with war buddies who go through the same joys and sorrows.

Yuuji moves forward on his path as a soldier to protect "an important woman": Asako. However, she leaves his side without waiting until he's reached maturity. Yuuji is yet again tormented by a sense of helplessness, but is saved by Asako's parting words and begins to be able to walk on his own two feet once more.