peripeteia
/ˌpɛrɪpɪˈtaɪə/
noun
- A sudden and unexpected change in a situation, especially in a story or play, that reverses the course of events.
- The hero's discovery that his long-lost friend was actually his enemy was a dramatic peripeteia.
- In the movie, the peripeteia occurs when the detective realizes the butler is the real criminal.
- The novel's peripeteia shocked readers as the kind old woman turned out to be the villain.