Reverend Abner Hale, a rigid and devout New England missionary, travels to the Hawaiian Islands in the early 19th century with his new bride, Jerusha Bromley. Abner's mission is to convert the native islanders to Christianity, but his strict and uncompromising methods clash with the local culture and traditions. Jerusha, who is more compassionate and understanding, finds herself torn between supporting her husband's mission and respecting the ways of the Hawaiian people. As they work to establish a church and school, the cultural divide becomes increasingly evident, creating tension not only with the islanders but also within their own marriage.

Amidst the beauty and challenges of the Hawaiian landscape, the missionaries encounter various obstacles, including disease, natural disasters, and opposition from both native leaders and other evangelical forces. Jerusha's empathy towards the Hawaiians begins to contrast sharply with Abner's unwavering dogma, leading to personal and professional conflicts. As they navigate their dangerous and often heartbreaking circumstances, their journey tests their faith, endurance, and ultimately their relationship. In the process, they both come to understand the profound impact of their presence on the island's people and culture.