City of Death is the second serial of the seventeenth season of the British science fiction television series Doctor Who, which depicts the adventures of a time-travelling humanoid alien known as the Doctor. It was produced by the BBC and first broadcast in four weekly parts between 29 September 1979 and 20 October 1979 on BBC1. The serial was written by "David Agnew" – a pseudonym for the combined work of David Fisher, Douglas Adams, and Graham Williams – and directed by Michael Hayes.

City of Death features the Fourth Doctor (Tom Baker) and his companion Romana (Lalla Ward). Set primarily in present day Paris, the plot concerns a scheme by Count Scarlioni (Julian Glover), in reality an alien called Scaroth, to steal the Mona Lisa to finance experiments in time travel in the hope of averting the accident that killed the remainder of his race four hundred million years previously, which began the existence of life on the planet as well.

The original storyline devised by Fisher was heavily retooled by script editor Adams, aided by producer Williams. It was the first Doctor Who serial to film on location outside of the United Kingdom; the production team worked in Paris during April and May 1979; studio work was completed in June.

Broadcast during a strike that took ITV (the BBC's rival) off the air, City of Death scored high ratings. The fourth episode was watched by over sixteen million viewers, the highest UK television audience ever attained by an episode of Doctor Who. Although retrospectively regarded as one of the best serials from the series' classic run, initial reception was mixed, with criticism of the humorous tone.[1] In September 2009, it was ranked as readers' eighth favourite story (of 200-to-that-date) in Doctor Who Magazine issue 413.

Plot

In Paris, the Doctor and Romana sense a time distortion. They observe the Countess Scarlioni using an alien device to scan the security systems housing Leonardo da Vinci's Mona Lisa at the Louvre. The pair meet Inspector Duggan, who suspects the Countess to be involved in an art theft scheme with her husband, Count Scarlioni. Duggan joins the Doctor and Romana in investigating the Scarlioni mansion. There, they discover Dr. Kerensky's temporal experiments, the source of the distortions, and six exact copies of the Mona Lisa. The Doctor instructs Romana and Duggan to continue investigating while he returns to the TARDIS to visit Leonardo. The Count successfully steals the real painting and captures Romana and Duggan after the Doctor leaves. Learning that Romana is familiar with time, he kills Dr. Kerensky and forces Romana to continue the tests.

The Doctor arrives at Leonardo's studio but is captured by another Scarlioni, who reveals he is really Scaroth, the last Jagaroth. His people arrived on Earth 400 million years ago, but the others died when their craft exploded, and his own body was fragmented across time. Collectively, Scaroth's fragments manipulated humanity to invent technology that will let him go back in time to stop the explosion. To finance his work, he employed Leonardo to create copies of the Mona Lisa to sell off after stealing the original. After Scaroth leaves, the Doctor escapes and writes "This is a fake" on the blank canvases before returning to the present.

Scaroth threatens to destroy Paris if Romana stops helping him. The Doctor tries to gain the Countess' help by showing Scaroth's true form, but Scaroth kills her. Romana completes the work and Scaroth uses it to travel to the past. The Doctor, Romana and Duggan follow him via the TARDIS, fearing that the ship's explosion created life on Earth, and if Scaroth should prevent it, humanity would not exist. Duggan knocks Scaroth out in time, returning the latter to the present, where he is discovered, unmasked, by his bodyguard. The ensuing fight sets the mansion ablaze, destroying Scaroth and the paintings save one marked copy. Duggan argues that they've lost an invaluable piece of art, but the Doctor assures him that the copy, still done by Leonardo's hand, will go unnoticed, and that art is worthless if its monetary value is all that matters before bidding him farewell.