Classic Doctor Who Season 14 Episode 12 The Deadly Assassin: Part 4

In the fourth and final part of "The Deadly Assassin," the Doctor continues his desperate attempt to stop the Master from accessing the Eye of Harmony, the power source that keeps the Time Lords' home planet of Gallifrey stable. With the help of Castellan Spandrell and Co-ordinator Engin, the Doctor infiltrates the Master's stronghold and thwarts his plan to use the Eye's power for his own gain. However, the Master manages to unleash chaos on Gallifrey, causing devastation and leading to a dramatic confrontation with the Doctor. As the two Time Lords battle for the future of Gallifrey, the fate of the entire universe hangs in the balance. Will the Doctor be able to stop the Master's evil machinations and save his home planet? The fate of all Time Lords depends on his success.