The Doctor pounds on the door with an oxygen tank, but they quickly begin to pass out. The Master arrives just in time to rescue him.
The Doctor is brought to the lunar governor and accuses him of trying to kill Dale for political reasons. Cross denies their accusations. The Governor decides to place them in solitary confinement for a year as punishment for trying to escape. The Master, not willing to wait a year to take custody of the Doctor, threatens to expose the Governor's plan to stage escapes and the Governor relents. The Doctor won't accompany the Master until he hears that Jo is on the spaceship.
The Doctor and Jo are placed in a cage on the Master's ship. They ask why they have been spared and the Master hints that his employers are interested in him. They are returning to the Ogron planet.
The Doctor's sonic screwdriver was taken from him but he has a string file in his boot. He and Jo hatch an escape plan.
After the ship takes off, the Doctor begins to tell Jo about his trial with the Time Lords. As he does, he surreptitiously files through the prisoner bars while Jo quietly takes apart the bedding. When the Doctor finally cuts through, Jo rigs up a dummy in the bedding and takes over the phony conversation while the Doctor dons a space suit and goes out of the airlock.
While the Doctor is moving around the ship, the Master has to make a course correction. The Doctor is flung off of into space. He disconnects his air hose and uses the escaping gas to propel him back against the ship.
The Master checks in with the Doctor and Jo. When Jo pretends the Doctor is asleep, the Master's suspicions are aroused. He takes a gun and returns to the cell.
The Doctor climbs up the ship and enters another airlock, reaching the flight deck. The Master, having realized the bluff, takes Jo hostage and puts her in the airlock without a suit. The Doctor, however, has doubled back to the cell and attacks the Master.
As they fight, a ship approaches and docks with them. They have drifted into Draconian space. The Master tries to bluff his way through, but the Draconians, owing to the tensions with Earth, pronounce a death sentence on him for violating their territory. The Doctor pleads to meet with the Emperor and the Draconians agree.
The Doctor, the Master and Jo are placed back in the cell. The Master, however, transmits a signal to the Ogrons…