At some stage, your protagonist needs to make a crucial decision; a critical choice. This is often when we find out exactly who a character is, as real personalities are revealed at moments of high stress. Watts stresses that this has to be a decision by the character to take a particular path – not just something that happens by chance.
In many classic stories, the “critical choice” involves choosing between a good, but hard, path and a bad, but easy, one.
In tragedies, the unhappy ending often stems from a character making the wrong choice at this point – Romeo poisoning himself on seeing Juliet supposedly dead, for example.
The critical choice(s) made by your protagonist need to result in the climax, the highest peak of tension, in your story.
For some stories, this could be the firing squad levelling their guns to shoot, a battle commencing, a high-speed chase or something equally dramatic. In other stories, the climax could be a huge argument between a husband and wife, or a playground fight between children, or Cinderella and the Ugly Sisters trying on the glass slipper.
The reversal should be the consequence of the critical choice and the climax, and it should change the status of the characters – especially your protagonist. For example, a downtrodden wife might leave her husband after a row; a bullied child might stand up for a fellow victim and realise that the bully no longer has any power over him; Cinderella might be recognised by the prince.
The resolution is a return to a fresh stasis – one where the characters should be changed, wiser and enlightened, but where the story being told is complete.
(You can always start off a new story, a sequel, with another trigger…)
I’ve only covered Watts’ eight-point arc in brief here. In the book, he gives several examples of how the eight-point arc applies to various stories. He also explains how a longer story (such as a novel) should include arcs-within-arcs – subplots and scenes where the same eight-point structure is followed, but at a more minor level than for the arc of the entire story.
You can buy Writing a Novel from Amazon.com – and I highly recommend that you do, as it’s an excellent book for any writer of fiction, and deals with all aspects of the craft (not just eight-point arcs!)