Peter Davison is on a new journey to discover everything he can about the Doctor's Companion. What exactly is a companion's role, how do you actually become a companion, what do they have in common and how have the companions changed over the years?

With the Griffins stuck at home during a blackout, Peter tells the story of "Star Wars Episode IV: A New Hope".

television series

television series (2000-2001)

British character-based comedy sketch show

The Doctor answers a summons and finally returns to his homeworld, Gallifrey, seat of the Time Lords. However, when the President of the High Council is assassinated, he becomes the prime suspect, while an old enemy lurks in the shadows, pulling the strings.

Intercepted while travelling between Earth and the Ark, the Fourth Doctor and his companions are transported to the planet Skaro on a mission for the Time Lords — to prevent the creation of the Daleks.

Arriving in London at the end of the 19th Century, the Doctor and Leela make friends with a police pathologist, Professor Litefoot, and learn that hairs taken from the clothing of a dead body found floating in the Thames seem to have originated from a very large rat.
The Doctor's investigations take him first to the sewers, where there are indeed giant rats on the loose, and then to the Palace Theatre, where a stage magician, Li H'sen Chang, is procuring young girls for his master, the ancient Chinese god Weng-Chiang. Weng-Chiang is in fact Magnus Greel, a war criminal from the 51st Century. The journey back through time has disrupted his molecular structure and he now needs to feed on the life force of others - hence his use for the young girls. He has come to London to retrieve his lost time cabinet, which is in the possession of Litefoot. Infiltrating Litefoot's home with Chang's ventriloquist doll Mr Sin - a computerised homonculus with the brain of a pig - he retrieves the cabinet and prepares to travel back to his own time.
The Doctor, aided by Leela, Litefoot and Henry Gordon Jago, the proprietor of the Theatre, tracks him down to his lair and traps him before he can escape. Greel falls into his life force extraction machine and disintegrates. The Doctor is then attacked by Mr Sin but manages to disconnect its circuitry, rendering it inanimate.

Finding out-of-season Brighton beach somewhat lacking, the Doctor and Romana travel to the leisure planet Argolis - but there strange experiments are taking place.

维基：

It was during this season that the Doctor cut ties to UNIT (after Terror of the Zygons, the Brigadier would not appear again until Mawdryn Undead in 1983, and The Seeds of Doom marked the last occasion to date that the Doctor was explicitly said to be working for UNIT - as opposed to working with them as occasions warranted). Several of the serials in this season, particularly Pyramids of Mars and The Brain of Morbius, are among the best-known of the 1970s-era storylines. Though it was aired as a part of Season 13, Terror of the Zygons was actually filmed as part of the previous season; this holdover allowed the series to switch back to an autumn season start.

The Doctor and Sarah reach Earth and try to warn the research centre about the Kraal invasion before Styggron unleashes his virus.

Philip Hinchcliffe era
The planet Karn is home both to a mystic Sisterhood, whose sacred flame produces an elixir of life, and to Mehendri Solon, a fanatical scientist who is using the remnants of spaceship crash victims to put together a new body for the still-living brain of the executed Time Lord criminal Morbius.
When the Doctor and Sarah arrive on the planet, Solon decides that the Doctor's head is just what he needs to complete his work. The Sisterhood meanwhile fear that the Doctor has been sent by the Time Lords to steal the last drops of elixir produced by the dying flame. They kidnap him and plan to burn him at the stake but he is rescued by Sarah, who is temporarily blinded in the process.
The Doctor is tricked by Solon into believing that his companion's condition is permanent. He asks the Sisterhood for help and restores their sacred flame to its former glory using a firework to clear its blocked chimney. Returning to Solon's citadel, the Doctor and Sarah become trapped in the cellar.
The Doctor releases cyanide fumes into the ventilation system and Solon is killed, but not before he has used an artificial brain case to complete Morbius's new body. The now-mobile Morbius accepts the Doctor's challenge to a mind-bending contest, which takes a heavy toll on both of them. The Sisters force the crazed Morbius over a cliff and he falls to his death. They then use the elixir to heal the Doctor.

The season is notable for the departure of Sarah Jane Smith in The Hand of Fear and for The Deadly Assassin, a story set entirely on Gallifrey which expounded greatly upon the culture and history of the Time Lords, and the Eye of Harmony and Rassilon are mentioned for the first time. The Deadly Assassin also featured the return of the Decayed Master in a degenerated form and had the Doctor without a companion for an entire story for the first time in the history of Doctor Who. This story is also the first time the limit of regenerations is set.