It's three years after the events of the original Battle Royale, and Shuya Nanahara is now an internationally-known terrorist determined to bring down the government. His terrorist group, Wild Seven, stages an attack that levels several buildings in Tokyo on Christmas Day, killing 8000 people. In order for the government to study the benefits of "teamwork", the new students work in pairs, with their collars electronically linked so that if one of them is killed, the other dies as well. They must kill Nanahara in three days - or die.

Young art student Hideo paints an unnerving portrait of Tomie, who whispers that she loves him. Inexplicably, he reacts by stabbing her to death with a painting trowel. Two friends, Takumi and Shunichi, arrive on the scene and help him dispose of the body. To cheer him up, the boys take the unwitting murderer to the nearest bar for a party... but a mysterious girl named Tomie shows up, bearing a few odd physical resemblances to the dead girl in the ground.

Takeshi Hongo is a man of extraordinary intellect, but his promising future is about to be maliciously snuffed out by and evil secret society known as Shocker. Reinvented against his will and transformed into a powerful experimental cyborg, Hongo will forever be known as Kamen Rider The First.