The New Doctor arrives on Earth in the middle of a freak meteor shower. Faceless killer shop window dummies are coming to life and killing anything that comes into their path while Facsimiles are replacing top Military, Political and Civil leaders. The Nestene has come to invade the Earth. The convalescent Doctor teams up with Brigadier Lethbridge-Stewart and Dr. Elizabeth Shaw of UNIT to thwart the Nestine's plans even as the invasion begins.

A world-class painter is taken ill and lies in the bedroom of an inn, while people down below squabble over his paintings and inheritance. The wily old man is unperturbed, even regarding the infernal trumpet sound which plays throughout.

In Scotland 1865, An old shepherd and his little Skye terrier go to Edinburgh. But when the shepherd dies of pneumonia, the dog remains faithful to his master, refuses to be adopted by anyone, and takes to sleeping on his master's grave in the Greyfriars kirkyard, despite a caretaker with a "no dogs" rule. And when Bobby is taken up for being unlicensed, it's up to the children of Edinburgh and the Lord Provost to decide what's to be done.

In 1921 Dublin, the IRA battles the "Black & Tans," special British forces given to harsh measures. Irish-American medical student Kerry O'Shea hopes to stay aloof, but saving a wounded friend gets him outlawed, and inexorably drawn into the rebel organization by his former professor Sean Lenihan, who has "shaken hands with the devil" and begun to think of fighting as an end in itself. Complications arise when Kerry falls for a beautiful English hostage, and the British offer a peace treaty that is not enough to satisfy Lenihan.

A Liverpool gang member wins a singing contest is then called up for National Service where he clashes with another soldier.

A look at the subtle (and not so subtle!) links to the show's past and future contained within the story of The Five Doctors.

Ibsen wrote An Enemy of the People as a direct response to the public's outcry over his earlier play Ghosts. Channeling his feelings into on Dr. Stockman, whose single voice of reason is drowned out by those with paranoid and ulterior interests, Ibsen had no qualms remarking on the irrational nature of the masses and the corrupt political systems which encourage them.