The Earthling All Alone (E29)

At UG Headquarters, the team learns about a new satellite from Dr. Niwa: a false identity, and is in truth a spy. Worse yet, with alleged superhuman abilities, Dan suspects him to be an alien. Soga is sent to spy on the spy under the pretense of visiting his fiancé, who believes she'd seen this alien before. The fiancé, Saeko, tells Soga what she knows about Niwa, and his assistant Ichinomiya. (Prime Video)