Things get boring for the team when they are forced to go on standby for a week after a mushroom-shaped Heterodyne with regenerating abilities appears. But events only take a turn for the worse when the Heterodyne activates and starts creating smaller mushrooms that destroy the surrounding city.

A new year has brought big changes for the company, with Director Nishijima stepping up to take over as company president following his orchestration of Ookouchi's dismissal. In the wake of this development, PR Division 2 receives a new tactical aide- Saeki, a former student of Shirota.

As if learning that her father was not the hero she always believed him to be wasn't bad enough, Ibuki's will and nerve became completely shattered when she had to fight against a Heterodyne almost identical to the one that killed him. Now, as Ibuki takes a vacation whilst she decides whether or not to pilot Dai-Guard ever again, the team must put up with Matsutouya, her manual-obsessed replacement.