"Sabimaru-Senpai is gone."

Houtarou laments his immaturity and weaknesses in the face of fleeting, yet endless suffering. How can he help Sabimaru? Just then, Houtarou is invited by Kajiki to call out a UFO whose sighting has recently become more frequent.

Houtarou and his friends find a possibility to rescue Sabimaru by befriending UFO-X. However, the Three Dark Sisters and Sabimaru with the Dreadriver appear before them! Equip yourself with the Number 10 Chemy and Change to Super Gotchard now, Houtarou Ichinose!