Chinese communists disguise a submarine as a sea serpent to shoo away fisherman from waters which they wish to keep for themselves, but they attract the attention of a larger creature which pulls them down into the depths.
Cole tells his psychiatrist how a comet eliminated all life on Earth except himself - he informs the psychiatrist that he's a hallucination. However, the psychiatrist maintains he's the last man on Earth and Cole is his own hallucination.