Professor Yuuko Kouzuki and Kasumi Yashiro's unique abilities facilitate Cadet Takeru Shirogane's return to his own world. Driven by a sense of urgency, Takeru turns to Yuuko for help in completing the Alternative IV project, the last remaining hope for humanity in their fight against the BETA, an alien species that has invaded and taken over the planet. As the race to finish the project draws to a close, Takeru and his fellow cadets bid farewell to the Yokohama pilot training academy. Unfortunately, Takeru and his squad are ambushed by the BETA during their Tactical Surface Fighter testing. Takeru narrowly escapes with his life, but not without witnessing the brutal death of someone close to him. Unable to fight any longer, Takeru escapes back to his own world, only to face yet another devastating blow of fate. According to Yuuko's theory, parallel universes suffer the same tragedies. Therefore, Takeru must find the strength to overcome his trauma if he is to protect those he loves.