The moody Korean thriller "Perfect Number," based on the Japanese novel by Keigo Higashino, has American remake written all over it. Think: "Body Heat," but without the body heat (an easy, inevitable fix for a stateside amp-up).
This Seoul-set story finds mild-mannered math teacher Suk-go (Ryu Seung-bum) so obsessed with his comely next-door neighbor, Hwa-sun (Lee Yo-won), that he offers to help cover things up when she unexpectedly murders her abusive ex-husband. Suk-go uses his numerical genius to devise the perfect alibi for Hwa-sun's crime (her live-in niece is also at risk), reassuring the object of his suppressed affection with a simple "trust me."
But the anxious collaborators are soon in defense mode when a dogged police detective (Jo Jin-Woong), coincidentally Suk-go's long-lost school chum, starts investigating. Along the way, Hwa-sun's kindly ex-boyfriend resurfaces, Suk-go's fixation with Hwa-sun becomes more evident (especially to her) and the cop's suspicions deepen — and shift.
Director Bang Eun-jin, working off a measured script by Lee Gong-ju and Lee Jung-hwa, slowly drives the tale's twisty components into an involving, if somewhat melodramatic third act. By the time the previously hidden details of Suk-go's master plan are unraveled — backed by a lushly heartfelt score — you half-expect Susan Hayward or Joan Crawford to enter frame instead of our lovestruck guy.