The Doctor is banished to Earth by his own people, with a new face and the knowledge removed.  He lands in 20th Century England where he is found and brought to the attention of the Brigadier.

Meanwhile, the Autons are attempting an invasion and are replacing senior members of government and the army and it is up to the Doctor, the Brigadier and newly appointed member of UNIT, Doctor Elizabeth Shaw, to stop them.

Read More Spearhead From Space