A meteor crashes into Crater Lake, the heat from the impact causing a prehistoric egg to hatch.
Alright, so the plot is just trash. But despite its obvious low budget, this comes across as one of the most gripping and entertaining monster-on-the-loose films in existence. There are also some good moments of humor. In an age filled so-called 'monsters' which are no more than laughable men-in-rubber-suit creations or lizards dressed up in frills and forced to rip each other to pieces (cheap exploitation-style), it's refreshing to discover that the Plesiosaur in this little gem is an excellent Harryhausen-style stop-motion creature.
Quite a hard film to find, but it's worth finding.