It’s obvious that the group embarking on this Antarctic mission had never seen "The Thing From Another World" (1951); otherwise, they would have understood that anything unearthed from the ice should simply be left undisturbed. The World Ecology Bureau makes a discovery—a seed pod—and quickly, the “Doctor” (Tom Baker) and “Sarah Jane” (Elisabeth Sladen) are on their way to investigate, only to find that whatever it is has been consuming resources and expanding in size. Complicating matters for our time-traveling heroes, we also learn that a well-known, albeit eccentric, plant enthusiast named "Chase" ("Camp Freddie" himself - Tony Beckley) has enlisted the assistance of “Scorby” (John Challis) to obtain the thing at any price. With the plant now growing rapidly and feeding voraciously, alongside the increasingly ambitious collector attempting to undermine their efforts to destroy the "Krynoid," it seems they face a considerable obstacle. I began to think that these series functioned more effectively as four-part stories; this one extends to six episodes, and the third and fourth installments feel like filler, not significantly moving forward what is otherwise a well-cast and amusing narrative. It’s also an installment where Sladen has a greater degree of involvement, and Beckley demonstrates himself to be a rather inventive adversary for his Time Lord opponent.

Source on TMDB