Act two is the middle of your story–the largest part, at least 50%. The best description of the second act I’ve ever heard came from one of Brandon Sanderson’s teaching videos on YouTube, which I highly recommend. He said that in act one, the protagonist reacts to the antagonist. In act two, the protagonist takes real proactive action, but it only makes everything worse.
When the second act begins, the protagonist is still learning about the ramifications of their decision to act. Sometimes they enter a whole new world, like when Bilbo left the Shire in The Hobbit or when Harry Potter came to Hogwarts. Or they might physically stay in the same world they started in, but it’s different for them now. The rules have changed, and this requires an adjustment. But whatever the nature of the changes, they must require the main character to grow.
Quite often at or near this point, the protagonist will acquire a new supporting character(s). Interactions between them offer opportunities for your character to grow even more. Harry made friends with Ron on the Hogwarts Express.
The first major landmark of the second act is the first pinch point. This applies pressure to your character, and reminds readers of the central conflict or your story. The first pinch point happens around 3/8 of the way through your book, or about 38%. In Harry Potter, this is where Harry faces the Sorting Hat, and the possibility of being put into Slytherin. It comes early in The Hobbit, but the first pinch point is the riddle-game with Gollum and the escape from the goblin tunnels. Gollum is an agent of dark forces, because of the Ring, and Bilbo must defeat him without any help from the dwarves or Gandalf. It is perhaps a good example, because it’s only about 30% of the way through the book. If you’re a novelist, don’t get hung up on hitting these points exactly. Close is fine for horseshoes, hand grenades–and novels.
Then there’s the midpoint, occurring roughly halfway through the book. If your book ends well for the protagonist, this is a low point. Conversely, if you’re writing a tragedy, this will be a happy event. Some of the stuff I’ve read indicates a shift from passive to active here, but I prefer to do that at the beginning of the first act. Still, it’s a good place for your protagonist to step up and become even more committed to action. Quite often, the stakes are raised here as well.
In The Hobbit, this is where Bilbo and the dwarves are captured by the spiders in Mirkwood. It’s a real turning point for Bilbo, killing the giant spider all by himself. He starts to believe that he can be a warrior, too, in his own small way. He commemorates this by naming his sword Sting. To continue with Harry Potter and the Sorcerer’s Stone, the midpoint was the battle with the troll. Harry and Ron had to step up and defend Hermione or she could’ve died.
Approximately 65% of the way through your story comes the second pinch point. Some sources say it’s best to have it linked to the first pinch point, which is fine if you can manage it. Still, in Harry Potter, this is when he discovers the Mirror of Erised, admits to himself his deep unmet longing for his family, and even engages in obsessive behavior, so much so that Dumbledore intervenes. And in The Hobbit, this is where Bilbo rescues the dwarves from the prison of the wood-elves. Since neither of these second pinches are related to the first, and it can be safely said that both these stories were extremely successful, I believe linking the pinch points is a nice touch, but hardly necessary.
The second act ends about 75% of the way through your book. If you are writing a tragedy, this will be your protagonist’s greatest victory, but one that carries with it the seeds of their coming defeat.
This is plot point number two (which tells us nothing), but for stories with happy endings, it’s also called the dark night of the soul, rock bottom, and the brick wall, which are considerably more descriptive. It can be a result of trying to fix the crisis at the midpoint. Sometimes the protagonist discovers the antagonist here and decides to confront him.Usually, there’s a renewed commitment to the decision which ended act one. In The Hobbit, Bilbo confronts Smaug, and the dragon flies off to Mirkwood to wreak havoc on the poor people of Laketown. And I’ll stray from Harry Potter, so as to give an example from an adult book here–in The Lord of the Rings, it is at this point that Sam realizes that Frodo, whom he believed dead, is still alive. But Sam has allowed Frodo to be captured by the enemy–with the Ring.
This point should truly hurt your character. (S)he must have salt instead of bandages on her wounds. It needs to elicit an emotional response from your readers, but to do that, it can’t just be a big cataclysm–it should cost your hero something personally, and you must show, not tell us how it happens. And paradoxically, this incredible low point should be what propels your hero toward his/her final victory.
The plan to save the day has utterly failed here. If the antagonist has been unknown, this is often when (s)he is revealed. The stakes have been raised yet again and the protagonist is overwhelmed.
And so ends act two.