Clotho captures a Level 10 Chemy for the Three Dark Sisters and subjects it to their creepy experiments, bringing them closer to completion of "something".

Meanwhile, Kugimiya and Harima from the Alchemys Union arrive at the academy and warn the students that there may be a mole within their ranks. However before he begins investigating on who the possible mole is, he heavily criticizes Houtarou's fighting style as a Kamen Rider.

The spy for the Three Dark Sisters turned out to be Shiori Harima, an investigator from the Alchemy Union. Houtarou lashes out in anger at Shiori, who attacks the Chemy, but is tormented by her use of forbidden alchemy.

Then the Three Dark Sisters appear. When Atropos and her sisters get their hands on a mysterious driver, they say "now it's your turn" to the mysterious warrior known as Kamen Rider Dread, and begin a new terrifying experiment.

Just who is this dark destroyer, Dread?