Fifteen years ago, Jack Harper, pilot of the S-class mech Avenger, led three mechs to repel the behemoth Kraken through a suicide detonation tactic. All crew members perished, and Jack was killed in action. Fifteen years later, he lives under an assumed identity as a D-grade mechanic at Green Vine City’s Seventh Repair Station, written off as useless by everyone — including his own son Oliver, now a B-grade commander. But when the A-rank leader of the Darkstar Legion bursts forth from the underground and Oliver’s life hangs in the balance, Jack climbs into the wrecked mech -0, which he has tended to for fifteen years. Right before his son’s eyes, he slays the formidable foe in just three moves. Everyone in command center who once mocked him falls silent, stunned. Yet an even crueler truth remains: the Three-in-One Core, fused from the energy cores of his three fallen comrades, only holds enough power for those three strikes.
