An Air Force crew from Anchorage, led bt Capt Hendry (Kenneth Toby), & a reporter, Scotty (Douglas Spencer), is ordered to check out a mysterious finding at a civilian research post in the arctic, Polar Expedition Six. There, Hendry is told by leader Dr Carrington (Robert Cornthwaite) that a 20 thousand ton flying object crashed nearby. Hendry states that's a lot for an aircraft, but Carrington adds: ' It is for the sort of aircraft we know, Captain. '. Via a magnetic fix, the group arrives at the crash site, and a large round form is seen below the ice: a flying saucer ? Hendry decides to use thermite bombs to melt the ice, but the explosion starts a vast fire underneath the ice. What is left in the ice is an 8-ft body. The group chops an ice block around it & takes it back for examination. With the block left in an open storage room, Hendry tells the scientists he must wait for further orders, but Carrington protests the body should be examined immediately. On guard, a skittish crewmember covers the block with an electric blanket. Awakened, the crewmember sees the Thing (James Arness) out of the iceblock & fires at it. The Thing escapes to the frigid outside, & is attacked by sled dogs. An arm from the Thing is retrieved. Under examination, it reveals that their visitor has a plant, not animal basis, & feeds on blood. Carrington's ass't, Nikki (Margaret Sheriden) advises Hendry that the Doctor is becoming obsessed with the Thing. Without warning, the Thing kills two scientists in the Greenhouse & plants seedpods.
It then cuts off the heat, and Hendry is determined to stop it using any means available.