Kamen Rider Build Episode 4

Sento was suddenly poisoned by someone with a cobra marking on his chest! The poison has caused Sento to remember another human experimentation memory. Sento remembers one side panel of the Pandora Box within the human experimentation site. A wounded Sento realizes that the Pandora Box will lead them to the secret organization, Faust. He asks Misora to gather information on the Sky Wall. Meanwhile, Ryuga arrives in Seito to protect Nabeshima's family, which could serve as a clue to solve his false murder charges. Faust suddenly appears before Ryuga who desperately attempts to protect Nabeshima's family...