Professor Lowson is searching the Wash for King John's lost treasure. Instead he awakes a reptilian creature buried in the mud, which seems to have arrived on this planet in a meteorite. It starts wandering around, killing and eating anybody it comes across. Lowson wants to capture it alive, his companions want to kill it before it kills anyone else. Soon the locals are involved and following a number of violent deaths and an attempted rape, there can only be a catastrophic finale.