Mack receives a note in his mailbox from "Papa", saying that he would like to meet with Mack that coming weekend at the shack. Mack is puzzled by the note—he has had no relationship with his abusive father since he left home at age 13. He suspects that the note may be from God, whom his wife Nan refers to as "Papa".
Mack's family leaves to visit relatives and he goes alone to the shack, unsure of what he will see there. He arrives and initially finds nothing, but as he is leaving, the shack and its surroundings are supernaturally transformed into a lush and inviting scene. He enters the shack and encounters manifestations of the three persons of the Trinity. God the Father takes the form of an African American woman who calls herself Elousia and Papa; Jesus Christ is a Middle-Eastern carpenter; and the Holy Spirit physically manifests as an Asian woman named Sarayu.
The bulk of the book narrates Mack's conversations with Papa, Jesus, and Sarayu as he comes to terms with Missy's death and his relationship with the three of them...