Doctor Who (1963) Season 17 Episode 21 Shada (1)

In Doctor Who season 17 episode 21, titled Shada (1), the Doctor and his companion Romana arrive at Cambridge University, where they encounter a professor named Chronotis. Chronotis, who is actually a Time Lord, reveals to the Doctor that he has a mysterious and powerful book in his possession called The Worshipful and Ancient Law of Gallifrey. However, before they can delve further into this discovery, the book is stolen by another Time Lord named Skagra, who wants to use its knowledge for his own nefarious purposes.

As the Doctor and Romana work to retrieve the stolen book and stop Skagra's plans, they discover that he is searching for the lost planet of Shada, which is said to contain a powerful secret. The Doctor eventually realizes that Skagra's true goal is to capture the minds of every intelligent being in the universe and use them to create his own galaxy-spanning consciousness.

In an effort to stop Skagra, the Doctor and Romana must seek the help of K-9, the professor, and a hapless human named Chris, who unwittingly becomes involved in their adventure. As they travel from Earth to Shada and beyond, they encounter a host of dangerous and bizarre creatures, including the vicious Krarg and the unpredictable Time Vortex.

Throughout the episode, the Doctor must use his quick thinking and vast knowledge of time and space to outwit Skagra and prevent him from achieving his goal. Meanwhile, Romana learns more about the Doctor's past and the history of their people, the Time Lords.

Ultimately, the first part of Shada sets the stage for an epic battle between the Doctor and Skagra, as they race to find the lost planet of Shada and unlock its secrets. As always, the fate of the universe hangs in the balance, and the Doctor and his allies must work together to prevent disaster.