Doctor Who City Of Death Part 1

While 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 ongoing art theft scheme with her husband, Count Scarlioni. Duggan joins the Doctor and Romana in investigating the Scarlioni mansion. There, they find equipment used by Dr. Kerensky to experiment in time, the source of the time distortions, as well as 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, a good friend of his. After the Doctor leaves, the Count returns after successfully stealing the Mona Lisa and captures Romana and Duggan. Learning that Romana is familiar with time, he kills Dr. Kerensky and forces Romana to continue the tests.

In the past, the Doctor arrives at Leonardo's home but is captured by Captain Tancredi, who is Count Scarlioni. Tancredi reveals he is really Scaroth, a member of the Jagaroth race. They had arrived on Earth 400 million years ago, but due to an explosion in their craft, all of the others died and his own body was fragmented across time. Collectively, the fragments of Scaroth have manipulated humanity so that by the 20th century, they will have technology that will enable him to go back in time to stop the explosion. Tancredi is currently employing Leonardo to create copies of the Mona Lisa in order to finance Scarlioni's work. After Tancredi leaves, the Doctor knocks out his captor, marks the blank canvases with a felt-tip pen with the phrase, "This is a fake", and leaves a message to Leonardo to paint over his writing before returning to the present.

The Doctor learns Scaroth threatens to destroy Paris if Romana does not continue the work. He tries to gain the Countess' help by showing the Count's true form, but he kills her. Romana completes the work and Scaroth uses it to travel to the past. The Doctor ushers Romana and Duggan into the TARDIS, fearing that the ship's explosion was the spark that started the development of life on Earth, and if Scaroth should prevent it, humanity would not exist. They arrive in time for Duggan to knock Scaroth out before he can reach the ship. Scaroth returns to present Earth, where he is discovered in his alien form by his bodyguard Hermann, and they get into a fight which damages the equipment and sets the mansion on fire. Hermann escapes, but Scaroth burns to death. By the time the Doctor, Romana, and Duggan arrive, the original Mona Lisa and 5 of the 6 copies have been burned in the fire, but the last copy remains safe. 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. The Doctor and Romana say goodbye to Duggan at the Eiffel Tower.