The Time Lords have taken control of the TARDIS, sending the Doctor and Sarah Jane Smith into dangerous territory... On the graveyard planet of Karn, the eternal Sisterhood fights to keep the sacred flame alive. High in the castle, the brilliant surgeon Mehendri Solon conducts gruesome experiments on living flesh. And as a storm approaches, evil from the depths of Time Lord history plots its return to the land of the living. But is even the Doctor's mind a match for the Brain of Morbius?