Set in the 1950s, John Groberg (Gorham) is playing in the band at a dance being held at Brigham Young University. Jean (Hathaway) is his girlfriend who is also at the dance. They end up dancing with each other, and they leave the dance together. John's family in Idaho Falls receives his mission call. He learns that he is called to serve in Tonga. He says goodbye to his family and leaves from Idaho Falls to Los Angeles, where he boards a ship and gets to Fiji where he is detained in a Fijian jail. He is released and sets sail for Tonga, where he meets his mission president who introduces him to Feki, his companion who is a native Tongan who also speaks English. They are assigned to serve in a remote island of the mission. He expects a warm welcome from the people, but he is greeted with contempt by the island people. He goes through culture shock as he adjusts to the Tongan culture, difficulty with the Tongan language with a local minister has told the people not to listen to John or to his message. He begins by learning the Tongan language. He isolates himself, studies the Bible in both English and Tongan and becomes more familiar with the language. John and Feki build a house for themselves on the island. One morning, John discovers that rats have eaten the soles of his feet. His fellow church members help him as his feet heal. They heal just in time for the Sunday church meetings, and he is miraculously able to walk. This astonishes the people, and they become more receptive to his message. One night, a group of men surround John and Feki to beat them up. They have been sent by the local minister. One of the men, Tomasi, breaks them up and sends them away. Tomasi saves John and Feki, because he was baptised into the church and is Mormon himself. Tomasi begins attending church meetings. A local woman, at the behest of her family, tries to seduce John so that she can have a "half White baby". The woman's mother becomes offended at John's rejection of her daughter. John tells her that he is saving himself for Jean, his girlfriend back home. The woman's mother is satisfied. A hurricane hits the island, and the island is heavily damaged. A supply ship is expected in a few weeks, but the ship is late. The people ration their food and water to survive. Many people on the island die. John is saved when the local minister approaches him, apologizes to him, and gives John his last ration of food. The supply ship arrives. John, Feki, and many others are saved. The local minister passes away and is given an honorable burial. The mission president authorizes John to form a congregation on the island. John is set apart as the branch president and calls two counselors. Feki is assigned to go back to construction. John and Feki part ways, and thank each other for their friendship. The new mission president visits the island and has concerns about the work there. Even though a lot of work has been done, the mission president has no records of the work. John quickly completes the required forms and turns them in to the mission president. The mission president apologizes to John and praises John for his work. He also puts John in for a six-month extension of his mission. While traveling to an outlying island, John and his two counselors are caught in a major storm at sea. All three are tossed overboard and must swim for their lives. John miraculously makes it to shore and finds that his counselors are also safe. Once John returns to the Tongan Island, he finds out the six-month extension is denied, and John concludes his mission to Tonga. The people thank him for all he has done for them, and John heads back home to the United States. Throughout his mission, John and Jean keep in contact by letters. Some of the narrative of the story is told through these letters. They remain faithful to each other and are married after John returns home. They have children and continue to serve in the church. They also visit the Tongan islands several times.
