Sento searches for the secrets between Faust and the Pandora Box in the next episode of Kamen Rider Build, When There’s Zero Testimony.
Sento (Atsuhiro Inukai) collapses from being poisoned by a mysterious monster with the mark of a cobra. Isurugi (Yasuyuki Maekawa) rescues him, saving his life, but who was the monster that appeared to be so similar to Night Rogue?
Sento remembers that the Faust test site has a plate that features the same pattern found on the Pandora Box. Is there a connection between the technology that transforms humans into the Smash and the Pandora Box’s powers from Mars? Sento obtains a “secret” concerning the Pandora Box, and he begins questioning Gentoku (Kensei Mikami) in regards to this “secret” to search around for his true intentions.
Meanwhile, Ryuga (Eiji Akaso) infiltrates into Seito and successfuly meets with the family of Nabeshima (Oomiya Ichi). In order to protect them from Faust, he tries to take them to Touto. However, a set of troops that look like Guardians appear before them.