Under the moonlit sky by a serene lake, a mysterious spacecraft descends upon the water's surface. From this vessel emerges a group who abducts Professor Katou, a leading figure in space engineering, and his family. Unaware of this abduction, the professor's second son, Yuuji, a talented American football player who had fled from home, finds himself in the midst of a game. Observing him are Mark, Dickey, Franco, and Yuri—a quartet of psychics honing their abilities in a clandestine facility. Convinced that the previous night's events signal an alien invasion, they opt to utilize their psychic powers to snatch Yuuji, believing they must summon the formidable robot, Baratack, to combat this threat. Only through the fusion of Yuuji and the other four psychics can Baratack be activated. As the five individuals, including the bewildered Yuuji, unite their strengths with a resounding cry of 'Pentagoras Unite!' the mighty Baratack materializes. Fueled by Yuuji's fiery determination, he embarks on a fierce mission to vanquish the Golteus reptilian army.