Act One is the guided tour that ends with the exits locking behind you. It teaches the reader how this story works: tone, stakes, whose side we are on, what kind of antagonist force is in play (person, system, or inner weather). Then it takes away the option of going home unchanged. That lock is half the pleasure of starting a novel.

Show the flawed equilibrium first. Life mostly works because of a strategy that will later break. Make it lived, not lectured. We should feel the groove of ordinary days so we notice when the needle jumps.

Introduce central pressure early enough for momentum, late enough that we understand what is being disrupted. A signal of trouble should be clear. Refusal or hesitation is human and useful. Characters stall for reasons. Those reasons reveal the wound.

The locking commitment can be public or private: a signature, a confession, a stolen object, a promise, a train boarded. After that moment, returning to the old life should cost more than moving forward. If they can shrug and go back to brunch, the door never closed.

Do not “finish introducing” forever. Readers forgive missing furniture. They do not forgive missing momentum. You can keep revealing the world in Act Two while the chase is on. In fact, revelation under pressure is more enjoyable than a lobby display.

End Act One with a new concrete goal for Act Two. Not “survive somehow.” Something filmable. Find the witness. Cross the border. Win the hearing. Break the code. The worksheet helps you name the lock. The prompts help you stress-test it. When the door clicks shut, the fun really starts.