Ep 12. Mawdryn Undead (4)

The Doctor and his companions find themselves caught in a time loop when they encounter Mawdryn, a former member of the Time Lord race. Mawdryn is searching for a way to break his eternal regeneration cycle and seeks the Doctor's help. Along the way, they cross paths with a group of Earth-based humans who have unwittingly stumbled upon a mysterious alien ship.

As the story unfolds and the Doctor unravels the mystery of Mawdryn and his ship, tensions mount among the various groups. The Doctor must navigate the various personalities and motivations of those he encounters as he seeks a solution to the problem at hand.

As always, there are plenty of twists and turns, moments of humor and drama, and a healthy dose of science fiction adventure. Fans of the long-running series will find plenty to enjoy in this episode, which also sets up further plot developments for the remainder of the season.