I reckon the TARDIS must be related to the shopping trolley - it never goes where it's supposed to! This time the "Doctor" (Jon Pertwee) and his new pal "Sarah Jane" (Elisabeth Sladen) are planning some leisure time in the sun when they find themselves directed to a planet where technology doesn't work! That doesn't put folks off coming there though as it's the main source of the rare mineral "Parrinium" which has remarkable medical properties. When a ship full of "Daleks" arrives too - unable to exterminate anyone, an uneasy truce breaks out as they must ally themselves against the warrior-like indigenous population. It's one of those people, "Bellal" (Arnold Yarrow) who tries to help the doctor explore the legendary city of "Exxilon" so they can disable it's power-draining beacon and maybe get out alive. It takes four episodes to tell the tale and even the presence of the "Daleks" doesn't really set the thing alight. It lacks that usual sense of mischief and depth of characters that the "UNIT" scenarios deliver and the logical puzzles at the end aren't designed to include the viewer at all. Someone had some fun setting fire to a load of polystyrene at the end, and it's quite fun watching a "Dalek" go for an unwanted dip, but otherwise this isn't really very good.