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
In the McCourts' world, when it rains, it pours. The move from America to Ireland is a catastrophic mistake. Ireland is cold, wet, and squalid. Daddy McCourt is an alcoholic who drinks away all the money and disappears for days on end. Angela McCourt's unable to provide for the children and they spend most of their life hungry, cold, and dressed in rags. Frank's a good schoolboy, up to the usual boy's antics, except always feeling the pressure to help his family and take care of his hungry little brothers.
Act II
Malachy Sr. leaves for wartime work in England and is supposed to send money from his job. Instead, he's all but disappeared. The family has to resort to burning the wood from the walls to keep from freezing, and Angela has to beg for help from local charities. Without the means to pay the rent, the McCourts are evicted from their home. They have no choice but to move in with Laman Griffin, Angela's alcoholic and abusive cousin. Eventually, Frank and Laman go at it, and Frank moves out.
Act III
As Frank gets older and is able to help financially, the McCourts get back together living under one roof. Malachy Jr. and Angela have jobs also and are able to afford a better life. Frank finds a steady job due to his smarts and tenacity and is able to buy the long-awaited ticket back to America. The memoir ends with Frank's boat docked on the shores of America where he hopes a better life awaits him.