Douglass's Narrative is like a highway map, showing us the road from slavery to freedom. At the beginning of the book, Douglass is a slave in both body and mind. When the book ends, he gets both his legal freedom and frees his mind. And if the book is like a highway map, then the mile markers are a series of "epiphanies," or moments of realization, that he has along the way. These events are turning points in Douglass's life, but they also help show how he got there, and what he had to learn along the way.
The first epiphany is Douglass's realization about what slavery is. He's born a slave on Colonel Lloyd's plantation, but as a child he's mostly spared the worst kinds of suffering. He sees his Aunt Hester get beaten, for example, but he's too young to be whipped himself. Instead, he suffers without really knowing it. He never knows his father and only meets his mother a handful of times before she dies – and then, he isn't allowed to go to her funeral. But he doesn't really know for a long time that this isn't normal. So his first turning point is sort of simplistic, but also important: realizing that he is a slave and all that that entails.
The second stage of his life begins when the seven-year-old Douglass is sent to work for a new set of masters in Baltimore. Baltimore is a whole new world for him, with a lot of new experiences, but the most important thing he learns there is the power of education. He has this second epiphany when his master's wife starts teaching him to read, which gets her in big trouble with her husband. Douglass finds ways of educating himself, but the real lesson is that slavery exists not because the masters are better than their slaves, but because they keep their slaves ignorant. Douglass starts to suspect that if slaves managed to educate themselves, it would be impossible to stop them from becoming free.
As Douglass becomes a young man, he starts fighting to actually be free. When he talks back to his master, his master sends him to work for a notorious "slave breaker," Covey, who tries to destroy Douglass's spirit. For a while it works, and Douglass is reduced to the state of mind of an animal. This is the lowest point in his life. His third epiphany happens, however, when he decides that he'd rather die than be treated like a slave anymore. So the next time Covey tries to whip him, he stands up to him, and after a two-hour fight, Covey leaves him alone. Douglass vows never to be whipped again. And he never is.
After this, Douglass bounces from master to master, but he's always on the lookout for a way to escape to freedom. And after one failed attempt, he finally succeeds and makes his way first to New York, then to Massachusetts. But even after he's free, he discovers that his journey isn't over. This is his final epiphany: even after he acquires his own freedom, he realizes he can't rest until all slavery is abolished. He not only becomes an abolitionist activist himself; he writes the narrative of his life to teach others, white and black, how to follow in his footsteps.