Schoolteachers Barbara Wright and Ian Chesterton are intrigued by one of their pupils, Susan Foreman, and visit her home address – a junkyard at 76 Totter’s Lane – where they meet her grandfather, the Doctor. The Doctor and Susan are aliens who travel through time and space in their ship, the TARDIS, which looks like an ordinary police box but actually houses a huge, gleaming control room. The TARDIS takes them all to a Palaeolithic landscape where they encounter a tribe that has lost the secret of fire…