Delivery boy Tenma Kudou becomes connected with a group which discovered an ancient, advanced war weapon as a power awakens within him while its being targeted by a rival squadron.
Needing a third member to activate their ChouSeiShin, Tenma decides to search for their partner, unknowing that the Flame Tribe's final member has been there all along.
Tenma is suddenly attacked by a new GranSazer from a third tribe who is trying to find his own alliance, making him susceptible to the Wind Tribe's manipulations.
Both the Flame and Wind Tribes try to reach out to the two remaining awakening members of the Earth Tribe: a girl associated with a criminal and the officer trying to bring him in.
While trying to deal with proving the innocence of Ran's partner from his enemies, the GranSazer of the Flame and Earth Tribe try to awaken the third ChouSeiShin while the Wind Tribe continues their assault.
When a co-worker of Tenma becomes hurt by Karin, he must work to save her life even knowing that his rival Dentsuin is the doctor performing her surgery.
With Ryoko and Jin defecting to the side of the allied GranSazer, Karin continues to manipulate Akira into helping her and to eliminate any obstacles that stand in her way.
When Naoto, the only GranSazer still working on his own, is attacked by the rampaging Akelon, Kamiya and Ran must try to convince him to join with them so that the nine GranSazer could finally fight together as one group.
Both Naoto and Akira must work through their trials and difficulties in order for the GranSazer to finally unite as one and face down the Akelon invader in a final showdown.
A meteor from space reveals a new invasive force while unveiling the fourth ChouSeiShin, which comes under protection even as a famed photographer does suspicious investigations of it and the GranSazer.