The Ribos Operation
In "The Ribos Operation," the Doctor and Romana are assigned a quest by the White Guardian to gather the six segments of the Key to Time, a powerful artifact that controls time itself. The first segment is disguised as a piece of the rare mineral jethrik on the primitive planet Ribos. The Ribos Operation was also the introduction of Romana I.
The Creature from the Pit
The Doctor, played by Tom Baker, arrives on Chloris with his companion Romana and attempts to negotiate peace and a trade agreement between Lady Adrasta and Erato. The plot takes a twist when the Doctor discovers that Erato is a living, intelligent creature, and the situation becomes more complex than a simple trade negotiation. Creature From The Pit was the introduction for Romana II.
Destiny of the Daleks
In "Destiny of the Daleks," the Fourth Doctor and Romana arrive on Skaro centuries after the events of "Genesis of the Daleks." The Daleks, caught in a stalemate war against the Movellans, seek the guidance of their creator, Davros, who is discovered in suspended animation. The Doctor becomes embroiled in the conflict, engaging in intellectual and ethical debates with Davros as they grapple with the consequences of the Daleks' creation.
The Horns of Nimon
In this serial, the Doctor and Romana arrive on the planets Skonnos and Crinoth, where the Nimon, minotaur-like aliens, manipulate the Skonnans into assisting them with a plan to invade Skonnos. The Nimons aim to create a tunnel in time and space between artificial black holes, posing a threat that the Doctor must thwart to save the planets from the Nimon's sinister plot.
The Leisure Hive
In "Leisure Hive," the Fourth Doctor and Romana visit the leisure planet Argolis. They encounter the Tachyon Recreation Generator, a machine designed to restore the vitality of the aging Argolins but inadvertently causing unintended consequences. The Doctor unravels a complex web of political intrigue and genetic manipulation, ultimately preventing a cataclysmic event and restoring balance to the troubled planet. In this serial, Tom Baker was introduced in his redesigned costume.
Meglos
In "Meglos," the Fourth Doctor and Romana respond to a distress call from the desert planet Tigella, where two factions are in conflict over the Dodecahedron, a powerful energy source. However, their intervention is disrupted when the shape-shifting cactus creature Meglos, seeking to harness the Dodecahedron's power, creates a doppelgänger of the Doctor to carry out its nefarious plan.
Warriors’ Gate
In "Warriors' Gate," the Fourth Doctor, accompanied by Romana and K9, becomes entangled in a surreal and time-disrupted universe. They encounter a mysterious gateway, a decaying spacecraft, and a race of enslaved beings known as the Tharils. As they navigate through the enigmatic realm, the Doctor confronts the ethical implications of the Tharils' plight and unravels the secrets of Warriors' Gate. This adventure was Romana’s last episode for Doctor Who. Warriors Gate was one of June’s favorite episodes that she worked on while apart of the production.
Logopolis
In "Logopolis," the Fourth Doctor faces the impending entropy and collapse of the universe, seeking the help of the mathematicians on the planet Logopolis. However, his encounter with the enigmatic Watcher and a new incarnation of the Master leads to a fateful confrontation that reverberates across time and space, ultimately leading to the Fourth Doctor's regeneration into his fifth incarnation.