On the planet Dido, the monstrous Koquillion terrorizes Bennett and Vicki, the only survivors of a crashed spaceship. When the TARDIS lands, the Doctor, Ian, and Barbara team up with Vicki to discover what Koquillion is hiding. (Originally broadcast in two parts.)

The Doctor and Ian reach the crashed spaceship and meet up with Barbara and Vicki, where the Doctor uncovers the truth about Koquillion.

The travellers decide to take a holiday near ancient Rome, but after a month the Doctor gets restless. He and Vicki determine to visit Rome, and while they are gone Ian and Barbara are abducted by slave traders. All roads lead to Rome, however, and the travellers find themselves at the mercy of the country's petulant emperor, Nero... (Originally broadcast in four parts.)

While the Doctor and Vicki meet with Nero, Barbara is taken to Rome to be sold while Ian is forced to work as a galley slave.

Ian and Delos are forced to fight each other for their freedom while the Doctor has to perform for Nero's court.

Ian and Delos manage to escape from Sevcheria and Tavius agrees to help Barbara rejoin them.The Doctor's attempts to avoid being thrown to the lions inadvertently result in Nero deciding to burn down Rome.

The TARDIS is drawn by a mysterious force and lands on the alien planet Vortis. There the Doctor, Ian, Barbara and Vicki find themselves caught up in a war between an evil force known as "The Animus", its ant-like Zarbi allies, and the butterfly-like Menoptra race and their allies the subterranean Optera.

The Doctor, Ian and Vicki are captured by the Zarbi while Barbara meets up with the butterfly-like Menoptera who are trying to reclaim the planet.

The Doctor is forced to co-operate with the Animus but Ian uses the opportunity to make an escape attempt.

Ian and Vrestin are captured by the subterranean Optera while Barbara and her Menoptera allies attempt to escape from the slave camp.

Barbara and the surviving Menoptera take refuge in the Temple of Light while the Doctor and Vicki attempt to escape by taking control of a Zarbi.

The Doctor and Vicki are taken before the Animus but the isoptope is left behind in the laboratory.The only hope of victory lies with Barbara and her Menoptera allies.

The TARDIS lands in the Holy Land during the Third Crusade and the crew help save Richard the Lionheart from an ambush, but Barbara is captured and brought before Saladin.

While the Doctor, Ian, and Vicki are drawn into the intrigues of King Richard's court, Barbara has to cope with an impatient Saladin and the vengeful El Akir.

Barbara allies herself with a man whose were murdered by El Akir as the Doctor and Vicki are caught up in Richard's plan to offer his sister's hand in marriage to Saladin's brother.

Ian sets out with a reluctant accomplice to rescue Barbara from El Akir's palace as the Doctor and Vicki try to evade the suspicions of the Earl of Leicester.

The TARDIS arrives on a planet that has been turned into a space museum but the Doctor and his friends are puzzled when they find themselves out of phase with their surroundings.

Now back on their proper time track, the Doctor and his friends must work to avoid the future they saw for themselves.

With the Doctor missing, Ian, Barbara and Vicki find themselves in danger from the Moroks while the Xerons also try to make contact with them.

While Ian tries to force Lobos to release the Doctor from the museum, Vicki joins the Xerons in trying to gain the weapons needed to start a revolution against the occupiers.

The Daleks pursue The Doctor through time and space, with the intentions of exterminating him. Places they land include the Mary Celeste, a haunted house and the empire state building.

While Ian and Vicki are threatened by a Mire Beast, the Doctor and Barbara meet up with the Aridians...who are then ordered to hand them over to the Daleks.

The TARDIS crew's attempts to escape from the Daleks take them to the top of the Empire State Building and a 19th century sailing ship.

The TARDIS lands in a haunted house where the Doctor and his friends are confronted by Dracula and Frankenstein's Monster...and then the Daleks appear.

With Vicki trapped on board the Dalek time machine, the Doctor, Ian and Barbara decide to make their stand on the planet Mechanus.

The Doctor and his friends are taken into the Mechanoid City but their troubles are far from over...especially when the Daleks launch an attack.

The Doctor, Vicki, and Steven Taylor, go to 1066 England, but something doesn't seem right including modern inventions like a Gramaphone and electricity. Could there be another Time Lord?

The Doctor is being held prisoner by the Monk and Steven and Vicki's search for him brings them to the Saxon village.But a greater danger threatens when a Viking raiding party arrives.

The Doctor manages to escape from his cell and get the upper hand on the Monk but his plans are derailed when Sven and Ulf arrive at the monastery.

The Doctor finally discovers what the Monk is up to and must move fast to prevent his opponent from altering the course of history.

After an encounter with a hostile robot called a Chumblie, the Doctor and his companions are rescued by a group of female Drahvins.

With the knowledge that the planet will be destroyed in two days, the Drahvins instruct the Doctor to help them steal the Rills' ship.

The Doctor and Vicki encounter the Rills and learn the situation is more complex than they thought while Steven finds the Drahvins' hospitality ever more perilous.

The Doctor and Vicki enlist the aid of the Chumblies to rescue Steven from the Drahvins and then find a way off the planet before its destruction.

The TARDIS lands in the middle of the Trojan War, where the Doctor is mistaken for the god Zeus.

While Odysseus forces the Doctor to find a way to win the war, Steven decides to get himself taken prisoner in order to enter Troy and find Vicki and the TARDIS.

With Steven and Vicki being held prisoner by the Trojans, the Doctor's only hope of seeing them again is to suggest the idea of the Trojan Horse.

The Doctor waits inside the Trojan Horse for a chance to reach his companions but Steven's assumed identity as a Greek soldier and Vicki's growing feelings for Troilus endanger their escape.