Is a remote turn-of-the-century lighthouse haunted by the spirits of the dead, or is the horror from beyond the stars? It's up to the Fourth Doctor (Tom Baker, who returns for the show's 15th season) and Leela (Louise Jameson) to solve the mystery, in "Horror of Fang Rock." Then, infected by an alien virus, the Doctor's only hope for survival lies with Leela getting him to a medical station on Titan and sending mini-clones of the Doctor and herself inside the Time Lord's brain, in "The Invisible Enemy," which features the debut of robot dog K-9 (voiced by John Leeson). In "Image of the Fendahl," the Doctor and Leela must stop scientists examining a 12-million-year-old skull from unleashing a powerful alien force that could devour the Earth. Next, artificial suns keep the overworked laborers of a far-future Pluto in perpetual daylight, in "The Sun Makers," and only the Doctor, Leela, and K-9 can help them topple the oppressive ruling regime. The Doctor and Leela assist the crew of a spaceship whose ancestors' lives were thrown into chaos by the well-meaning interference of the Time Lords, in "Underworld." And, it's anything but a pleasant visit home, in "The Invasion of Time," as the Doctor and Leela's journey to Gallifrey leads to an attack by alien invaders and the Doctor accused of being a traitor!26 episodes on 7 discs. 10 3/4 hrs. Standard; Soundtrack: English; Subtitles: English.