Seasons & episodes

S15 · E25The Invasion of Time (5) 1978-03-04 · 25 min＋

The Sontarans have invaded Gallifrey, seeking to seize the incredible power of the Time Lords. The Doctor's first step is to cut them off from their fleet. But Kelner is helping the enemy…

S15 · E26The Invasion of Time (6) 1978-03-11 · 25 min＋

The Sontarans finally invade the TARDIS itself, seeking the Great Key. The Doctor, however, has other uses for this powerful object…