The Key to Time, starring Tom Baker as the Fourth Doctor, is a seven-DVD box set containing the six linked stories of Doctor Who's 16th season, along with a huge array of extras. In The Key to Time, the Doctor and his new companion, Time Lady Romana (Mary Tamm) are dispatched by the White Guardian to recover the six segments of a powerful device with the ability to stop time.

Episode Listing:

The Ribos Operation: The Doctor and Romana trace the first segment of the Key to Time to the planet Ribos, where they encounter two con artists who are engaged in a scam to sell the entire planet to the Graff Vynda-K, deposed ruler of Levithia.

The Pirate Planet: Douglas Adams penned this episode in which the tracer detects the second segment on the planet Calufrax. The TARDIS makes a bumpy landing, and the Doctor and Romana soon discover that they are not on Calufrax at all.

The Stones of Blood: The search for the third segment of the Key leads the Doctor and Romana to the English countryside and an ancient stone circle called The Nine Travellers. But the third segment is nowhere to be found.

The Androids of Tara: The tracer brings the TARDIS to the planet Tara. Romana finds the fourth segment disguised as part of a statue, but is then taken prisoner by Count Grendel of Gracht.

The Power of Kroll: The search for the fifth segment of the Key to Time lands the Doctor and Romana in danger. The Doctor is shot and Romana is kidnapped.

The Armageddon Factor: The search for the Sixth (and last) Segment of the Key to Time bring the Doctor, Romana and K9 to the planet Atrios, where they encounter a interplanetary war and Princess Astra.