The Doctor's Powers

The Doctor and her companions rescue a space bullet train from a Cyberman attack, but Dan is nearly killed, so he parts ways to return to his life. A renegade Dalek contacts the Doctor, claiming that the Daleks need to be destroyed. Kate Stewart informs her famous artworks have been defaced by the Master and seismologists have been abducted. Reuniting with Tegan Jovanka and Ace, the Doctor learns the Master, his CyberMasters and the Daleks plan to end humanity by setting off lava from volcanoes worldwide. The Doctor is lured by the renegade Dalek, leaving the Daleks to capture her. The Master sends a miniaturised Ashad to Tegan, which acts as a portal to bring the Cybermen to UNIT. The Daleks take the Doctor to the Master in 1916, who forces her to regenerate into him. An AI program leads Ace to meet with Graham O'Brien to destroy the volcano machine, Tegan to destroy the Cyberman converter, and Yaz and Vinder to force the Master to undo the Doctor's transformation. The Master mortally wounds the Doctor, causing her to regenerate into the Fourteenth Doctor, who discovers that he has regained the form of his tenth incarnation.