The story takes place in a small city called Xingyuan City.

On Mount Shishio in the city, there stands a huge object shining with colorful light. This object named “Mono's Corner” actually stood there after the “Monster Day” incident 16 years ago.The “ monster's horn”.

After the “Monster Day” event in which monsters appeared all over the world at the same time, monster disasters began to become a daily occurrence.While Japan's Earth Defense Force began to use force to deal with monsters, the Kaiju Scientific Investigation and Prevention Center (SKIP Scientific Kaiju Investigation and Prevention center) also continued to conduct scientific surveys and evacuation in various areas in order to prevent the occurrence and expansion of monster disasters.guide.To this day, this organization is still investigating the reasons for the appearance of “Monster Day” and the “Mono Corner” in the city.

“Yuma”, who was only 7 years old, was attacked by a monster while camping with his parents in Shishitail Mountain. He miraculously survived without any injuries.Taking this as an opportunity, “Yuma” embarked on the path of studying monster biology.Although he had a painful past, Yuma did not lose his dream. He relied on the power of “imagination” to grow up. He joined “SKIP” as a novice investigator and was assigned to the Xingyuan City branch.

At this moment, a large-scale monster disaster occurred in Xingyuan City.“Want to protect these desperate people in front of me!” The moment this strong and direct thought emerged from the bottom of his heart, “Yuma”'s mind appeared in “Yuma”'s mind, “Lutian”, the messenger of light he had seen in his childhood, was talking to him.:“I am you, you are me... Release your imagination!”

The mysterious light that appears in the hand wraps Yuma's body, and the released power of imagination combines light and people, and the giant of light who protects the future “Ultraman Arc” transforms! Yuma, Ultraman Arc and important partnersTogether, chase the never-ending dream and start running from now on!