Cheaply done fast-food sci-fi that actually works pretty well for the most part. A small British isle inexplicably has temps soar into the 90's, in the dead of winter when the temp should be around 30. A mysterious scientist named Dr. Hanson (Christopher Lee) is seen sneaking around and bizarre noises can be heard from time to time by the few island residents.<br /><br />The movie carefully builds tension of the unseen danger, by scattering a few clues about the nature of what the islanders are up against, without showing the menace until deep into the film. Lee has shared the screen with Peter Cushing before, and does here again. Cushing is a local medical doctor, who, like most of the characters, hangs out at a pub owned by an author named Jeff Callum (Patrick Allen). Good acting by the entire cast, and the characters are developed well.<br /><br />There's some good old time "monster encounter" action at a spot called (love this name) "the pit", and the film's "unseen monster" approach works well because of it. When the creatures aren't around, the film provides for plenty of interesting subplot conflicts among the characters.<br /><br />There are a few clichés, but they were probably fresher plot devices in the '60's when this was made. The big negative on this movie is the abrupt and poorly thought out ending, which nullifies most of the value of what the characters had been doing throughout the whole story. It's like they simply ran out of money, and quit.<br /><br />The movie has a dud ending, but otherwise it's a good watch for better than average sci-fi.