Repeat after me Part 1:
PART ONE OF TWO: When the shuttle bus the Doctor is riding on is attacked, the most frightened passenger, Sky Silvestry, seems to be the most affected. The Doctor's attempts to get her to speak make her repeat what she is told. The delay between what the Sky repeats get shorter until she begins speaking in unison with them. If Sky isn't in control of herself, then what is? Amazing performances from the BBC series Doctor Who

Repeat after me Part 2:
PART TWO OF TWO: Whatever was in Sky is now in the Doctor, or that is what the passengers think. They want to throw the Doctor out of the door, but the Hostess and another passenger, Dee Dee try to stop them because they can see that Sky has stolen his voice. Can the Doctor be saved, and who will have to sacrifice themselves in order to do so?

Credit: BBC Worldwide