"Do you have... what it takes to be a hero?" It all starts when a mysterious space sage asks Yuma Hize this question. The mysterious man entrusts Yuma with challenges that surpass the limits of his imagination with a stake too high... "Should you fail... then you... will lose your power as Arc." Protecting Hoshimoto City alongside the SKIP's members, the bonds of trust created between the members, the conflicting feelings arising from trying to understand the meaning of defeating kaiju... Earning the powers of Ultraman placed the weight of these responsibilities upon Yuma. Now, these very burdens are twisted by Sascal, who manipulates them, sending challenge after challenge toward Yuma. Battling giant kaiju, an evil alien bent on destruction, and a warped dimension where even time itself is distorted, Yuma must confront the ultimate test. Will he...will Ultraman Arc overcome the greatest challenge yet and protect the future, surpassing the limits of the power of imagination?

In Hoshimoto City, a kaiju horn stands on Mt. Shishio. Yuma, a survivor of K-Day, joins SKIP to study kaiju. During a new disaster, he transforms into Ultraman Arc to protect people, guided by a mysterious light being.