On this episode of Perception...
A man named Cobra admits to one of Daniel's professor friends that he is a CIA agent who has been sanctioned to kill in the US.
The professor winds up dead.
Daniel learns that "Cobra" is merely a pathological liar who made the whole conspiracy up. His girlfriend who believed everything he said, killed the professor after she feared he would expose her "CIA" boyfriend.
Kate confronts Donnie about his cheating past. She also confronts the girl he cheated on her with. She admits to Donnie that she has trouble getting over it.