Mutsuki wishes that he will be the strongest Rider by fighting against the Tiger Undead but loses instead. But while confronting the Giraffa Undead, the Tiger Undead learns the truth behind the "Battle Fight" before facing Tennoji and his creation: The Titan.

After being poisoned by the venom of the Scorpion Undead, one of the two Undead fused into the Titan. Mutsuki attacks his friends and turns into the Category Ace. Everyone is not spared even his girlfriend, Nozomi. The Tiger Undead has already been sealed and Mutsuki is forcing himself to fight Blade in his King Form. Will the transformation be complete or a failure?

All the Riders get together to fight the Titan, and Blade's King form finds a new attack combo, the Four Card.