The perfect alibi of a genius mathematician begins!
Seok-go (Ryu Seung-beom), who was known as a genius but is now living a normal life as a high school math teacher, learns one day that Hwa-seon (Lee Yo-won), who moves in next door, accidentally killed her ex-husband. Gypsum designs the perfect alibi for her, who has been secretly watching, and surprisingly, Hwa-seon passes through the lie detector and gradually moves away from the suspect. However, Min-beom (Cho Jin-woong), the detective in charge of this case, is convinced that Hwa-seon is the culprit with an animalistic sense and begins to pursue her tenaciously.
Will the alibi set up by the genius mathematician Gypsum save her?
