A scientific expedition to Loch Ness runs into trouble when the group leader is killed in a mysterious diving accident. Soon after, when the unorthodox Professor Howell shows up to take over as leader of the group, more strange incidents and attacks start to occur. While Howell and TV producer Elizabeth Borden are busy investigating the source of the attacks, the body of an enormous sea creature washes up on the lake's shore.

A scientific expedition to Loch Ness runs into trouble when the group leader is killed in a mysterious diving accident. Soon after, when the unorthodox Professor Howell shows up to take over as leader of the group, more strange incidents and attacks start to occur. While Howell and TV producer Elizabeth Borden are busy investigating the source of the attacks, the body of an enormous sea creature washes up on the lake's shore.