In the conclusion of the four-part story "The Horns of Nimon," Romana discovers that the Nimon is a parasitic race, and that, far from intending to help the planet Skonnos restore its empire, the Nimon plan is to feed upon other races throughout the universe, utilizing radioactive crystals as a means of teleportation. It is up to the Doctor to nip the Nimon in the bud. Written by Anthony Read and originally telecast on January 11, 1980, "The Horns of Nimon" turned out to be the final Doctor Who episode of the series' 17th season, due to an unexpected BBC strike. ~ Hal Erickson, Rovi