Ren's past comes to light as both he and Yui return to Shiro's last known whereabouts and the birthplace of Kamen Rider Knight, as well as Eri's fate following the secret experiment's aftermath. When Yui finds nearly dead Professor Ejima in the Room 401, he blames Yui for causing a disaster before he dies.

With Ren doubting his ability to go through killing other Kamen Riders, Shinji and Miyuki contemplate his possible paths and the potential doom that he faces. As Sanako decided to go out for her 'secret association meeting', Yui continues to investigate the truth behind the secret experiments her brother conducted. Meanwhile, Shuichi attempts to release a prisoner.