Go Tell it on the Mountain is a novel that does a ton of looping back into characters' memories through the form of flashbacks, but let's just get the basic storyline straight (without those pesky trips down Memory Lane).
John Grimes wakes up on his fourteenth birthday, a Saturday, but no one in his family remembers that it's his big day. His mom gives him breakfast and tells him to go sweep the living room, just like every Saturday. Ouch.
But: surprise, surprise, she remembered. When he's done with his chores, John's mother, Elizabeth, gives him money and tells him to go buy something he'd like. He takes off and heads out of Harlem into Central Park. John spends his money at the movie theatre to watch a movie that his father would be sure to find sinful.
After the movies, John goes back home to find his brother, Roy, bleeding on the couch. His mother, father, Aunt Florence, and little sisters are all there, super upset because Roy has been stabbed. Gabriel, the father, slaps Elizabeth, the mother, for not keeping her kids safe. Roy says that he'll kill his father if he ever touches his mother again, and Gabriel gives him a beating with his belt. Yup, Gabriel beats a) his son, who has just b) been stabbed, with a belt. Talk about insult to injury.
John goes to church to clean up before the Saturday evening service and wrestles with Elisha, the preacher's nephew. Some older ladies come in and they start singing and praying. John's parents and aunt come in later, and his aunt cries while she prays. It turns out that she has a deadly illness and is frightened. Fair enough.
Elisha is overcome by the spirit of the Lord and lies on the floor, speaking in tongues. Soon John, too, is struck down. He passes through some terrible visions before he comes through it, saved by Jesus. Everyone is thrilled, except for Gabriel.
On the way home in the morning (it was an all-night prayer sesh), Elizabeth remembers John's real father, a boy she had loved but who had killed himself before John was born. Meanwhile, Florence tells Gabriel that she knows about the secret child he had with a woman he wasn't married to, and threatens to tell everyone his secret.
When they finally get home, John and Gabriel stand in the doorway, looking at each other unhappily. Not exactly a happily-ever-after