Five youths begin their battle against the underground forces of Tube as Maskman after they begin a war with the surface with the abduction of the mysterious Mio.

Takeru abandons Commander Sugata's Aura Power training when he receives a message from Mio about her survival and current whereabouts as Tube prepares to punish her.

As Emperor Zeba plunges the world into eternal darkness, the Maskman must complete their Aura Power training, even as Prince Igum decides to face Takeru for the shame Mio has brought him.