In The Shack we follow Mackenzie Phillips’ (Mack). Mack has five children, two of them are out of the house. On Labor Day weekend, Mack takes his three youngest children, a son and two daughters, camping at Wallowa Lake near Joseph, Oregon. Mack’s wife, Nan, is unable to join them. They spend the long weekend there exploring the area and having a good time. On the last morning, the older of the two children on the trip, go for one last canoe ride on the lake. It is at this time that disaster strikes. While on the canoe, it flips, trapping his son below the surface of the lake. Mack’s instincts kick in and he leaves his five year old daughter, Missy, alone at the camp site. He rushes to the lake to help his son, and eventually frees him. After preforming CPR, the son coughs up blood and disaster seems to be averted, until Mack realizes that Missy is missing.
Frantically, Mack begins to search for Missy with the help of other campers, and they soon realize that they need help and the police are called in. No evidence of where Missy went has been left behind, until Mack realizes that there is a ladybug clip on the table that did not belong to Missy. This leads the cops to deem the kidnapping to being done by who they call the “Ladybug Killer.” The only thing of Missy’s that is found is her blood stained clothes. The family has a memorial service for Missy and try to move on with their lives.
This time becomes known as “The Great Sadness.” One winter day, Mack receives a note asking him to come to the Shack, the place where Missy’s clothing had been found. This letter appears to be from God, as it is signed ‘Papa’ a name used by the family when talking to God. Mack heads to the Shack, and is greeted by three people, God the Father, Jesus Christ, and the Holy Spirit. Mack spends time with these three as they help him come to terms with Missy’s death and his relationship with them.