In Park Chan-wook's audacious and genre-defying film, a devout priest's faith is tested by a monstrous temptation. Song Kang-ho delivers a captivating performance as Sang-hyun, a man of the cloth who volunteers for a medical experiment, only to emerge with a miraculous recovery and a horrifying new craving for human blood. His crisis of conscience deepens when he is drawn into a dangerous liaison with Tae-ju, a lonely friend's wife played with haunting intensity by Kim Ok-bin. As Sang-hyun grapples with his violent desires and crumbling morality, his world spirals into a gothic nightmare of passion, betrayal, and macabre humor. Blending visceral horror with profound drama, this tale explores the dark corners of sacrifice and the terrifying price of eternal life, all under the masterful direction of the visionary filmmaker behind Oldboy.