Paris, France, is known as the City of Lights, a metropolis renowned for romance and beauty. Beneath the bustling streets and cafés, however, exists The Catacombs, a labyrinth of crumbling tunnels filled with six million dead. When a video camera containing mysterious footage is discovered deep within their depths, a group of friends venture into the tunnels to investigate. But what starts out as a lighthearted adventure takes a turn for the worse when they reach their destination—and stumble upon the evil lurking there.