Well clearly this Antarctic expedition had never watched "The Thing From Another World" (1951) before they set off else they would have known that anything you find buried in the ice ought to be left well alone! The World Ecology Bureau discovers a seed pod - and swiftly the "Doctor" (Tom Baker) and "Sarah Jane" (Elisabeth Sladen) race to the scene only to discover that the thing has been snacking, and growing, and isn't pocket-sized any more. Adding to the challenges for our intrepid time travellers, we also learn that renowned, and slightly bonkers, plant collector "Chase" ("Camp Freddie" himself - Tony Beckley) has engaged the help of "Scorby" (John Challis) to secure the thing for him at any cost. With the plant now growing exponentially and feeding accordingly as well as the increasingly megalomanic collector trying to thwart their plans to destroy the "Krynoid", it's looking like quite a challenge. By now, I felt that these series worked better as four-parters. This one runs to six and the third/fourth episodes tread water a bit too much without really advancing what is quite a well cast and entertainingly written story. It's also one where Sladen takes more of an active role and Beckley proves to be quite an imaginative foil for his antagonist Time Lord.