TARDIS is the latest invention of Dr. Who. A Time And Relative Dimension in Space machine, it can transport passengers to another world, at another time. With his granddaughters, Barbara and Susan, Dr. Who demonstrates the machine to Barbara's boyfriend, Ian. Ian trips and stumbles against the control panel, and the four humans are instantly ejected away from earth. They land in a vast, petrified forest, and soon Dr. Who finds himself involved in a terrible struggle as the peaceable That people fight for their survival against the terrible domination of the monstrous Daleks.