A group of unwitting police officers discovers a sinister underworld lurking behind a trapdoor during a routine investigation in an abandoned building. What begins as a standard call quickly spirals into chaos as they encounter a disturbing Black Mass. As they delve deeper into the nightmarish realm, they confront their worst fears and face unthinkable horrors. The line between reality and madness blurs, leading them into a harrowing fight for survival against dark forces that threaten to consume them all.