From the liner notes

In The Reeds, a weekend boating trip through the Norfolk Broads becomes a terrifying, deadly ordeal for six 20-something year old friends. Aboard the Corsair Star, a small cruiser rented from Mr. Croker, the local marina operator, the boating party loses its bearings and cuts through the vast reedy tidewater in search of the main channel. After the first casualty by a freak accident, the boat runs aground. Every effort to preserve themselves and find a way out fails, as one by one the friends are terrorized by young punks and killed by a hooded man with a gun. There is no escaping this vast waterway, a place of endless return, presided over by Croker who killed a group of young people decades before and initiated the hellish curse which traps all who take passage on the Corsair Star.