Shin Getter Robo is the third Getter Robo series chronologically (taking place after Getter Robo G but before Getter Robo Go).
Years after the original story and in a brief time of peace, Professor Saotome has completed his masterpiece, the Shin Getter Robo, while humanity makes large advancements in space exploration and Getter Rays research. Unfortunately, this progress brings them to the attention of a mysterious and hostile race from across time and space.