The Sazer-X team find a mysterious boy who claims to have amnesia, meanwhile, an ancient evil has awakened and begins consuming the people of earth. Bosquito, an extremely powerful evil being from ancient times has absorbed the power of the Justirisers and is using it to fuel its own minions. Sazer-X, the Justirisers, and the Gransazers must work together to defeat this villain and save the planet.

Sometime ago, this world was created by a girl, and was then destroyed by her in order to vent her frustration towards the reality. It was Gridman the Hyper Agent, the humane monster she created, Yuta Hibiki and his friends who saved her heart. Yuta Hibiki had just become a second-year high school student and decided to reveal his feelings to his classmate, Rikka. However, Kaiju suddenly appeared and began to attack the city. Gridman came back from the alternate dimension and told Yuta that worlds of different dimensions which were once in harmony were rapidly losing their balance. When the red dragon Dyan Rex, the Gridman's supporters named “Neon Genesis Junior High Students”, and the residents of an alternative world, Yomogi Asanaka and his friends appeared one by one, Yuta was once again caught up in a great crisis…

The story is set in the Shimane Prefecture, which supposedly has the fewest lawyers in all of Japan. Nakama plays the role of the hard-working and righteous Yamazaki Mizuho, who travels around by bicycle to help her clients.

Devils that lurk within humans, and family that is deemed irreplaceable to humans. With these two words, a new story in which familiar characters clash with passion. After a long battle, the Igarashi Family and their friends have finally achieved peace. However... a new threat that transcends Giff, the progenitor of the demons, has appeared.