  robot is the first serial of 12th season in the british science fiction television series doctor who, which was first broadcast in four weekly parts from 28 december 1974 to 18 january 1975. it was the first full serial to feature tom baker as the fourth doctor, as well as ian marter as new companion harry sullivan. == plot == following his third regeneration, the doctor briefly becomes delirious and then falls unconscious in front of sarah jane smith and brigadier lethbridge-stewart of unit. the brigadier has lieutenant harry sullivan take the doctor into his care. soon, the doctor wakes, eludes harry, and tries to sneak off in his tardis, but the brigadier and sarah jane stop him, convincing him to help in finding the culprit in the theft of top secret plans for a disintegrator gun. the brigadier takes the doctor to the ministry of defence advanced research centre where the plans were stored, where the doctor observes crushed flowers and a rectangular footprint. unit sets to protect factories where critical parts for the gun are manufactured, but find the culprit is able to outwit them, including burrowing up underground to collect the final component necessary for the weapon. meanwhile, sarah jane investigates the national institute for advanced scientific research, colloquially known as the "think tank". there, she find
1974_television_episodes 1975_television_episodes Doctor_Who_serials_novelised_by_Terrance_Dicks Fourth_Doctor_serials UNIT_stories