In 1215 at the castle of Ranulf Fitzwilliam, son Hugh is jousting on a matter of honor against Sir Gillis Estram, the champion of King John, when the TARDIS appears. The Doctor, Turlough and Tegan are immediately hailed as demons and welcomed warmly by the King. Something is wrong with this picture, observes the Doctor.

England, 1215. With the historic signing of the Magna Carta supposedly only days away, the Doctor is startled to find King John apparently intent on provoking civil war - and seemingly in two places at once...