Inside the firey Greta Garbo, Daisaku plummets into the icy depths of the Himalayan mountains. Gynrei and Tetsugyu desperately seek for their fallen comrade who has been sucked into the darkness of the snowy mountains. As Daisaku lay unconscious, he dreams of his past and the origins of Giant Robo. When Gynrei and Tetsugyu finally track down their friend, Tetsugyu must fight his greatest battle ever.