The Doctor and a newly-regenerated Romana arrive on Skaro to find that the Daleks, locked in a war with the robotic Movellans, have returned to retrieve their buried creator Davros.

After the TARDIS collides with a spacecraft delivering human tributes to the evil bull-like Nimon, the Doctor and Romana must stop the fearsome alien's quest to rule the galaxy.

The Doctor and Romana follow a distress signal which leads to the jungle planet Chloris, whose ruthless ruler Lady Adrasta harbors a deadly creature in a pit.

Sam, a quiet West Indian working as a London Transport ticket collector, strikes up an unlikely, but warm, friendship with Joe, an old man who has a room in the same house.

Benedick and Beatrice fight their merry war of words. But when Beatrice's friend, Hero, is humiliatingly jilted by Benedick's best friend, Claudio, Benedick has to choose which side he's on. But unknown to all, Claudio's been tricked by the bastard Don John, and (unfortunately), it's up to Dogberry and Verges to solve the case.

Romana fancies a proper holiday and convinces the Doctor to visit the leisure planet Argolis, where a takeover by the Argolins' historic enemy is underway.

On the lush planet Tigella, two opposing factions are divided over the usage of the Dodecahedron, an ancient and powerful artefact which provides the entire planet's energy. The Doctor is summoned to arbitrate the conflict, but the power-crazed Meglos intercepts the call and impersonates him in order to steal the Dodecahedron.

After an encounter with the Master, an airline stewardess named Tegan Jovanka becomes an unwitting stowaway aboard the TARDIS as it travels to the planet Logopolis. There, the Doctor discovers that the Master's interference with the Logopolitans' advanced mathematics has unleashed a wave of entropy which threatens to consume the entire universe.

The Doctor, Romana, Adric and K9 encounter the enslaved time-sensitive Tharils, who lead them to a white void occupied only by the ruins of an old building and a spaceship - a dimension that might be the key to escaping E-Space.

Noble Moroccan Othello finds his life with beautiful, fiercely loyal Desdemona thrown tragically out of balance when secretly jealous, scheming confidante Iago begins an insidious campaign of lies and treachery.