由少女．新条茜所创造的世界一度是「怪兽」肆虐之地，经过「Gridman同盟」的一番努力，成功开解少女封闭的内心，世界才恢复和平，不致毁灭。 危机结束一年后，响裕太决定向六花告白，谁知怪兽突然来袭，再次打破他们的日常。而Gridman亦再度回归，告知裕太「世界的平衡正在崩坍」。随着真红之强龙Dyna Rex、Gridman的支援者「新世纪中学生」，甚至异世界的居民陆续出现。谜样的敌人藏于暗处，「世界崩塌」的真相未明，Gridman同盟应如何应战？裕太珍藏已久的感情又能否成功传达？
在都立杜鹃台高中放学后的教室里，响裕太反复在笔记本上画着又擦去那个应该存在于他记忆中的GRIDMAN。这个世界曾经被一名少女创造并破坏，最后是来自异次元的电光超人GRIDMAN，和那名少女制造出来拥有心的怪兽，以及裕太一行人，拯救了那名少女的心。 升上高中二年级后，裕太决定向分发到不同班级的六花（宫本侑芽 配音）告白。然而，和平的世界与日常生活却随着轰隆巨响开始崩坏。就在裕太等人面临危机之时，GRIDMAN突然现身，并说道“这个世界的平衡即将瓦解。”。 不久，深红的强龙DYNAREX、GRIDMAN的助手‧新世纪中学生，以及来自另一个世界的麻中蓬等人出现在裕太面前。
就读不如归台高中一年级的麻中蓬，某日放学后偶然与自称『怪兽操控者』的谜样男子失马邂逅。此时，一只巨大怪兽突然现身城镇之中，失马随即变身为巨大机器人「DYNAZENON」迎战，麻中蓬与在场的同学们南梦芽、山中历、飞鸟川千濑等人因而被卷入这场激烈战斗之中，众人之后与失马一同组成「失马队」迎战接二连三来袭的怪兽……
Sequel to the 2018 animated series SSSS.Gridman and the third installment of the Gridman multimedia franchise. When Yomogi Asanaka, a first-year student at Fujiyokidai High School, meets Gauma, he claims to be a "kaiju user." But the appearance of a kaiju followed by the entry of the gigantic robot, Dynazenon, backs up his mysterious words. After ending up in the wrong place at the wrong time; they get dragged into the desperate fight against the kaiju!
Bob, a guardian from the Super Computer, helped by his friends Dot, Enzo, and dog Frisket, defend the digital city of Mainframe from evil computer viruses that seek to dominate the city and infect the entire net.
Tsuburaya Pro, Takara, and Trigger joint venture and direct sequel to the 1993 tokusatsu series "Denkou Choujin Gridman". Yuta Hibiki can’t remember who he is, and now he’s seeing and hearing things that others don’t! A voice from an old computer tells him to remember his calling, and he sees a massive, unmoving creature in the distance. Nothing’s making sense—until the behemoth springs to life! Suddenly, Yuta is pulled into a computer, reappearing in reality as the colossal hero—Gridman!
