Rumours abound of sinister goings-on in the ancient Massachusetts seaport of Innsmouth. The once prosperous town, which has fallen into a state of decrepitude and decay, is a stopover destination for Robert Olmstead, a young historian on a tour of the region. Despite hearing ominous tales of the town and its grotesque inhabitants, Olmstead feels compelled to explore Innsmouth. He finds the place almost deserted, except for a few inhospitable locals with strange, unblinking eyes - the so-called, Innsmouth Look. He meets the town drunk, Zadok Allen, who tells him the terrifying history of the town, about Devil Reef and mutant humanoids, sea gods, gold, and human sacrifice. The deranged ramblings of a madman? As night falls on Innsmouth, Olmstead soon has cause to wonder. The Shadow Over Innsmouth is an integral part of what has become known as H.P. Lovecraft's Cthulhu Mythos.