What that does is force the protagonist to stop, regroup, assemble perhaps a new set of skills or apply a new strength. It creates conflicts because what might seem to be feasible in the first half no longer works. For example:
Someone the protagonist trusted is proved untrustworthy.
Someone the pro believed to be an enemy becomes an ally.
Something the pro believed is proved false (like his parentage or his cause’s moral rightness).
The protagonist’s role is reversed: The detective becomes the suspect, the hunter becomes the hunted, the insider becomes the outsider.
(Remind me to think about this—this is usually an event that happens to the protagonist, rather than an action the pro takes, though it can happen in response to an action… why—because the character has to be blindsided, which is hard to do when the pro is dictating the action.)
This is the event that often turns the protagonist from a character into a hero—because merely reacting no longer will work. She can’t go on being merely what she was before—because that doesn’t work. She has to become something else also, something that can solve the problem, whatever it is.
Let’s generate some examples.
In The Godfather, the reversal comes (I think) when Vito is shot, because he is revealed to Michael not as the all-powerful father, but as a victim in need of protection (and Michael, in protecting him, is drawn into the family business).
In The Fugitive, Harrison Ford jumps and thus frees himself from being hunted, and becomes the hunter himself (calling Tommy Lee Jones to tell him, “I’m going to find the one-armed man”). Notice that the protagonist role shifts here— is Tommy Lee or Harrison the protagonist of the second half?
In Gone With the Wind, the reversal happens when Scarlett is seeking shelter from the war and goes home to Tara, only to discover that there is no surcease, that Tara has been damaged by the war, that the mother she longed for is dead and the father she needed has gone mad.
In Pride and Prejudice, it comes when Lizzie gets the letter from Darcy and realizes he had his reasons both for loving her and resisting it. Notice that the proposal (however unexpected) isn’t the reversal—that merely hardens her existing prejudice against him.
Okay, your suggestions here. Take some famous movie or novel and tell us what you think is the reversal, and where it happens, and what it changes.
Oedipus the King?