Manhole

Su Cheol is a serial killer who uses the city sewers down a manhole as his secret hideout. Late one night, a young girl witnesses Su Cheol's killing and he abducts her. Later, her older sister, Yeon Seo, determined to find her lost sister, discovers the manhole and goes down. As Su Cheol's blazing madness explodes due to the uninvited guests in his manhole, the two sisters stand against him in desperate attempts to escape out. Will they be able to escape the underground maze of the city that no one suspects?