Haruki taichō ni yòu Ware, Musashi wa shōnen erīto-tai ni nyūtai. Sekkyoku-teki ni kaijū o mamoru to kataru Musashi. Mizuki fuku taichō wa, erīto-tai wa kaijū o horoboshitai wakede wa naiga, genjitsu ni wa mamorenai koto ga ōi to tsugeru. Keisuke wa, Musashi o jissen ni sanka sa se reba wakaru to iu. Iiowaruto sugu ni, Musashi ni saisho no ninmu ga shita sareru. Kaijū garumedi o mamoru to ketsui shita Musashi wa, yūkan ni genjitsu ni idomu. Kaosu uirusu no kyōi ni tachimukau tame, Urutoraman kosumosu wa moesakaru taiyō no honō no yōna akairo kyosei ni henshin suru.
Invited by Captain Haruki, Musashi joins the Youth Elite Team. Musashi says he will actively protect the monsters. Vice Captain Mizuki tells him that the Elite Team doesn't want to destroy the monsters, but they often can't protect them in reality. Keisuke says that he can understand it by letting Musashi participate in a real battle. As soon as he finishes speaking, Musashi's first mission comes. He is determined to protect the monster Galmedy and bravely challenges reality. In order to deal with the threat of the Chaos Virus, Ultraman Cosmos turns into a red giant like the burning flames of the sun.
