One day, college student Keiko, who is looking for a job, learns that the person she had feelings for has committed suicide. Keiko wonders if she was the cause of this. Classmate Mami, through her boyfriend Takuya, tries to introduce Keiko to Kazuo, a member of Takuya's theater company. However, Keiko, who met Takuya, has a special feeling for him. Miyata, a young man who seems to be hiding in the darkness of everyday life, meets Keiko one day.
The time of the New Generation Heroes is drawing to a close. Hiroyuki is being targeted by a dark power, forcing the other Ultra Heroes, from Ginga to R/B to appear and help the Tri-Squad battle these evil forces. But among them is Taiga's father? What has happened to Ultraman Taro?!
Somewhere on a distant planet, X and Geed were defeated by a pair of black Ultramen who bore their likenesses in appearance. At the same time, an old enemy of Taro named Ultra Dark-Killer targeted both Zero and Grigio, forcing Taro to recruit the New Generation Heroes to stop the League of Darkness.
The New Generation Ultras team up to fight the League of Darkness, an evil organization led by Ultra Dark-Killer, made up of a selection of foes previously fought by the Ultras, along with evil clones of existing Ultras, including Dark Ultramen; X Darkness, Geed Darkness, Orb Darkness, and Zero Darkness
The mysterious Ultraman, Tregear, has suddenly appeared in Ayaka City. Tregear asks what one would do to make their dreams come true, prompting Katsumi to search for his own dream. As a monster appears for the first time in a year, Ultraman Blu and Ultraman Rosso are joined by Ultraman Geed to face off against this new threat. Walking towards their dream with the heart of the Minato family in hand, Ultraman Gruebe is born.
The two main characters, Katsumi and Isami Minato, are brothers who live with their younger sister and father who runs a specialty store. One day, they found the R/B Gyro and R/B Crystals, which transforms Katsumi into Ultraman Rosso and Isami into Ultraman Blu.