For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
Douglass is born a slave and spends his childhood discovering what it is to be a slave. At first, he only sees terrible things happen to others, like his Aunt Hester.
Act II
As Douglass gets older, he starts to actually experience the suffering of slavery himself. But being punished and whipped regularly only makes him more rebellious. So his master sends him to Mr. Covey, a well-known "slave breaker," to be beaten into submission. For the first six months, this works.
Act III
After six months of punishment, Douglass decides that he would rather die than be whipped again. This resolve helps him escape to freedom. Once he's free in the North, he joins the Abolitionist movement to end slavery.