The Doctor is finally free of the Black Guardian trying to have him killed and Turlough is relieved. But when the Tardis arrives in the year 1215, Tegan wonders if it's another Black Guardian trap. The Doctor assures her it isn't. What is odd though, is the Tardis arrives in the middle of a joust, witnessed by all. In attendance is King John, who warmly welcomes the Tardis crew, calling them his demons. He has them sit with him during the rest of the joust. The Doctor takes it in stride, but assumes something is wrong.
The joust is between Sir Ranulf Fitzwilliam's son Hugh and the Kings champion Sir Gilles Estram. When Hugh is unhorsed, the Doctor intervenes to stop a senseless death. The King takes his Demons advice and spares Hugh, much to the dismay of Hugh who feels dishonored. Ranulf is grateful to the Doctor for saving his son and gives him a place to rest up before they eat a meal. While Turlough is off investigating, the Doctor informs Tegan that King John is an imposter, as he should be in London taking the Crusader's Oath.
When Sir Geoffrey de Lacy arrives, he also claims the King should be in London as he just left him there that morning. Estram is outraged by the 'lies' and orders de Lacy to be executed. The Doctor intervenes once more. Estram is 'insulted' by the support Geoffrey is given so challenges the Doctor to a duel. Fitzwilliams is worried because Estram is the greatest swordsman in France, to which the Doctor replies "Fortunately, we are in England".
Borrowing a sword from Fitzwilliams, the Doctor battles Estram in a duel and wins. This time the King announces there must be a death. The Doctor can choose either Geoffrey de Lacy or the Master. Reluctantly, the Doctor allows the Master to be placed in an Iron Maiden, but it turns out to be the Masters Tardis. Using his prestige as the winner, the Doctor feigns to put Geoffrey in the dungeon, but it's a ruse to get to see the dungeons where he hopes to find the Masters Tardis. Getting to the dungeons, he sets Geoffrey free and tells him to go to London to warn the king but Geoffrey is killed along the way.
The Master uses the opportunity to discredit the Doctor and claims he killed Geoffrey. Now turned against the Doctor, Lord Ranulf Fitzwilliams seeks to kill the Doctor. Meanwhile, the Doctor has found the Masters tardis and sets a trap for him, using his TCE he earlier acquired after winning the duel. He hopes the Master won't notice, as he's likely to leave in a hurry. Continuing his search, the Doctor finds the king, who is actually Kamelion. Kamelion is an android with the ability of changing his appearance. Though a 'small time crime', the Masters goal is to rob England of the Magna Carta.
When the Doctor learns Kamelion is psycho-kinetically controlled, he hopes to gain control of it to foil the Masters plan. The Master challenges the Doctor to a battle of wilts over Kamelion and is winning when suddenly the two are discovered by Fitzwilliams and company. The Master loses concentration and the Doctor quickly forces Kamelion to transform into Tegan. Quickly grabbing 'Tegan', he runs into the Tardis where Tegan already is. Turlough grabs a sword and holds the Master off as he too runs into the Tardis.
PLANET OF ORIGIN: Discovered on Xeriphas by the Master
REASON FOR JOINING: After being freed from the Master's control, Kamelion joins the Tardis crew, much to the dismay of Tegan.