Six feature length volumes comprise the entire search made by the spaceship Tardis for "The Key to Time." The fourth doctor (Tom Baker) is joined by Romana (Mary Tamm) in this search in which they encounter giant squid-like gods, space pirates, and bitter 32-year winters. Episodes included: "The Ribos Operation,""The Pirate Planet,""The Stones of Blood,""The Androids of Tara,""The Power of Kroll," and "The Armageddon Factor."