The Seeds of Death - Episode 4

Exciting stuff, here, even with the Doctor out of action. The exterior filming is superb, cool shots and plenty of menace. The foam spreading is very effective. I wonder how scary it seemed at the time, seeing as how "Fury from the Deep" a few months ago (roughly) also featured deadly foam. There's some good tension in several scenes, and the cliffhanger with Zoe being approached by the threatening Ice Warrior particularly well done.