The book begins as McCourt lands at Albany, New York, and quickly makes his way to New York City. Friendless and clueless about American customs, he struggles to integrate himself into American blue-collar society. He is then drafted into the US Army, sent to Europe, and rises to the rank of corporal. On his stay in Germany, he has confrontations with many people who try to show Frank how to get a Russian refugee girl to have sexual intercourse with him by giving her coffee or cigarettes. He is granted leave from the army as compensation for his exceptional service as a clerk-typist and goes back home to Ireland to see his family. He then decides to return to the US, where he attends New York University ? despite never having graduated from high school. He falls in love with, and eventually marries, a middle-class American-born girl, Alberta Small, he meets at college.
After graduating from NYU, he teaches English and social studies at McKee Vocational and Technical High School on Staten Island. There, he is forced to deal with apathetic, indifferent students. Eventually, he moves on to teaching at the prestigious Stuyvesant High School. At Stuyvesant, he revises his teaching style to end his reliance on books and other teaching resources, to become an effective teacher.
'Tis examines Frank's relationship to his family and his wife during this time (all his siblings and his mother move to America over the course of the book). Eventually, Frank's relationship with his wife turns sour, and they stay together as long as they do only because of their daughter, Margaret Ann (named after Frank?s sister who died in infancy, and his grandmother, who is described in Angela's Ashes). Nonetheless, Frank finally leaves them, an action he compares to that of his father leaving his family.
Frank's mother, Angela McCourt, is in increasingly bad health due to emphysema and dies in New York around the same time as Frank's father, Malachy McCourt, Sr., dies in Ireland. Frank goes to Ireland to bury his father and scatter his mother's ashes. The book ends after Frank and his brothers scatter Angela's ashes over the graves of her family.
"'Tis" was the final and only word of the last chapter of Angela's Ashes, while 'Tis ends with the spreading of Angela McCourt's ashes in Ireland. Frank McCourt has remarked in several interviews (perhaps joking) that he originally intended for each book to have the other's title.