After the alien plant that Smith smuggled aboard grows to monstrous proportions and threatens to destroy the Jupitar 2, John attempts to burn the fatal foliage off by entering a nearby planet's atmosphere only to provoke the ruler of the planet (the last surviving 'Sobram warrior', Abraham Sofaer in purple-face) to first attempt to shoot down the saucer and then to coerce one of the crew to take his place on the 'dead' planet. The premise, that the militaristic caretaker would only give over command of the planet to someone ruthless enough to defeat him in an war-game and that all of the humans were either too incompetent or too honourable to do so, leaving only the robot, stripped of his memories and 'emotions' as a potential foe, is interesting (especially the revelation that the Will's amiable robot-buddy is only one reel-of-tape away from being a soul-less AI-terminator). Too bad the storyline then deviates to a ridiculous conclusion involving the surviving fragments of Smith's plant, who have imprinted on the deceitful Doctor, and move about accompanied by childish 'boing-boing' sound-effects. The failure of the writers (and therefore of the characters) to grasp even the basics of biology and astronomy is once again on display when Penny and Judy are discussing the astrogation and immenseness of space and later, when the planet is declared life-less despite the abundant vegetation and the term 'parthenogenesis' is tossed about meaninglessly (egregious scientific illiteracy was so permeating in seasons 2 and 3 that one wonders if it was some kind of 'in-joke' amongst the writers). Don't wait around for the planet to burst into flames.