The second round of the Jyamato Grand Prix has begun! The final goal of this "Sengoku-era Game" is to steal the Vision Driver from General Niram, the ninja Keiwa, and the swordswoman Neon, who face the Jyamato themselves.

Michinaga transforms into Buffa and goes straight for Niram's headquarters, but Ace appears as a ronin to stop him as Geats Boost MarkII. He is able to overwhelm Buffa and protect the Vision Driver.

Meanwhile, Ziin approaches Niram to get answers regarding the secret Ace's usage of Boost MarkII. Just what secrets is Ace hiding?