The TARDIS lands in a space museum on Earth in the late 21st century, where the Doctor, Jamie and Zoe learn that contact has been lost between Earth and the Moon. In this era, a form of instant travel called T-Mat has revolutionised the Earth, and now its people have lost interest in space travel. The Doctor and his companions travel to the Moon in an old-style rocket and reach the Moonbase, control centre for T-Mat, only to find a squad of Ice Warriors have commandeered the base, and plan to use the T-Mat network to their advantage.