Four adventurers descend to the bottom of the sea. When their surface tether snaps, they find themselves marooned in a network of underwater caverns.

Concerned about her brother who disappeared during his scientific expedition into the Himalayas, where he was searching for the elusive yeti, Connie Hayward sets out to scale the Himalayas. During her trek, she survives attacks by groups of vicious yetis. When she arrives at her brother's final campsite, she encounters a mysterious native guide who harbors a sinister secret.