When a dangerous "Arc-dissolve" entity suddenly appears in Odaiba and targets the DAKT headquarters, the military is left shorthanded with most pilots away on vacation. Kyosuke and Hikaru are urgently recalled from their intimate retreat to deploy their Siegfried units and repel the attack. Amidst the chaos, a brutal interrogation regarding the secrets of "GEHENNA" suggests that the enemy's arrival may be linked to a larger conspiracy.
DAKT engages in a desperate struggle to stop the destructive entity Arc Dissolve from leveling Ginza and Shinjuku. Amidst the chaos, a potent mental attack triggers repressed traumas in the pilots, leading to a complicated emotional encounter between Kyosuke and his teammate as she attempts to overwrite her past. Although they launch a coordinated strike on the enemy's core, Arc Dissolve vanishes after harvesting critical data, leaving the survivors to grapple with their psychological scars.