Ep 7. The Invisible Enemy: Part 3

The Doctor and Leela are in a race against time as they try to stop the Nucleus, a deadly virus which has taken control of the Titan space station's crew, from infecting all of humanity. In this third and final part of "The Invisible Enemy" storyline, the pair confront the virus and its hordes of infected people, now transformed into terrifying monsters.

The situation is dire as the station hurtles towards Earth, with the Nucleus determined to use its power to infect and destroy all life on the planet. Meanwhile, the Doctor's mental link with the virus, which has given him the ability to tap into its thoughts, is starting to have dangerous side effects. As Leela battles the infected crew, the Doctor risks his own sanity to try and find a way to stop the Nucleus before it's too late.

The tension is palpable as the Doctor and Leela navigate the labyrinthine corridors of the space station, fighting off infected crew members and trying to outwit the Nucleus. With time running out, they must use all of their skill and knowledge to try and save the day. But with the virus seemingly one step ahead of them at every turn, can they succeed in their mission?

Featuring some of the most iconic moments of the Classic Doctor Who era, "The Invisible Enemy: Part 3" is a must-watch for fans of the show. From the eerie, foreboding atmosphere of the infected space station to the pulse-pounding action of the Doctor and Leela's desperate escape, the episode offers a thrilling ride from start to finish. With strong performances from Tom Baker and Louise Jameson as the Doctor and Leela, respectively, the story manages to balance high-concept sci-fi with the character-driven drama which has made Doctor Who such a beloved show over the years.

Overall, "The Invisible Enemy: Part 3" is a fitting conclusion to one of the most memorable story arcs of the Classic Doctor Who series. Combining nail-biting suspense with unforgettable moments of humour and heart, it's a perfect example of the show's unique blend of genres and themes. Fans of science fiction, action, and drama will all find something to love in this classic episode, which remains as thrilling and entertaining as ever.