As the flames rise, Sarah uses her magic powers to make it rain, putting out the fire (and giving Katy Froade an almost fatal case of hypothermia). The outlaws rush out of the crowd and attack the guards while Sarah unties Gemma. There follows a long and spectacular fight arranged by Terry Walsh. The Count, the Bishop and the surviving guards retreat into the castle and shut the gates.
The Martian leader berates the Count for his failure, and the Count berates the Martians for not helping enough. The leader says it would be best to kill everyone but the Count disagrees because he needs people to rule. The Martians reluctantly agree.
The outlaws debate what to do next. Bill Crimson (Robert Russell) wants to storm the castle, and Gemma agrees with him, but the hooded man says it won’t work. Sarah says they need to think of a trick.
The Martians talk to each other in secret. One says they don’t need the Count and should kill him along with the rest. Another says they must wait until they can bring the rest of their kind to Earth, which depends on a certain planetary alignment.
The Count demands that the Bishop marry him to his cousin, but the Bishop refuses, saying it would be incestuous. The Count is furious, shouting “who will rid me of this turbulent priest?” and kicking the jester again.
Sarah and some of the outlaws attack the front of the castle and try to set fire to the gates. Meanwhile, Gemma and the rest of the outlaws sneak aroung the side of the castle with some ladders. As the outlaws (some anachronistically wearing DM boots) start to scale the walls, an electrical charge blows the ladders away and sets fire to them. In front of the gates, Sarah is hit in the chest by a crossbow bolt and falls to the ground.
The outlaws carry Sarah away, apparently dead. Gemma and her outlaws run away as the guards shoot at them. Gemma returns to Sarah and is distraught, but Sarah suddenly wakes up. She says that her body can heal itself if hit by primitive weapons such as these. The outlaws are disgruntled and say that crossbows are the latest thing. Sarah, Gemma and outlaws discuss what went wrong with the attack. They realise the Martians must have known that they were coming, but why didn’t they fight themselves? Sarah works out that the Martians must be waiting for a planetary alignment that will occur on midsummer’s day (although the episodes are very obviously shot in winter). She says it is the greatest threat to humanity for thousands of years. Bill Crimson retorts that it can’t be much worse than the Normans.
The hooded man finally removes his hood to reveal that he is the banished Sir Robert. He draws his sword and vows to fight to the death. Sarah notices something odd about the sword. Sir Robert says it was made by ancient wizard. Sarah looks closer and explains that the jewel in the hilt can divert and focus the Martian beam that will bring the rest of them to Earth.
The Count and the Bishop decide to kill the Martians. They order the guards to attack, but the Martians shoot back with death rays. The Count runs to top of the tower. The Martians slowly approach and throw him off. The Bishop escapes and takes sanctuary in the cathedral, praying for God to save him.
The Martians switch on the beam from the top of the castle. Sarah and Sir Robert go to the top of the cathedral. As Sir Robert holds his sword above his head, the beam jumps from the castle to the crystal (in a model shot that was far less spectacular than it sounds). Sir Robert points the tip of his sword towards the castle doors, which glow and then disappear. Gemma and the outlaws rush in and disable generator. The Martians come in, pointing death rays, but Sir Robert appears just in time and kills them with his sword.
As Sir Robert, Lady Eleanor and Bishop Godfrey go to the cathedral for the wedding, Sarah and Gemma quietly slip away.