A hopeful clergyman, “Fr. Joseph,” portrayed by Kerwin Matthews, comes to a secluded French Polynesian island to replace the tired and irritable older “Fr. Matthew,” played by Spencer Tracy. The parish consists of a leper colony alongside a prison. When the priests enlist some hesitant prisoners—including “Harry” (Frank Sinatra)—to assist with repairs in the village for those suffering from leprosy, these men initially display prejudice and resistance. However, an eruption resembling Krakatoa disrupts everything, sparking an idea among the convicts about potentially escaping. Naturally, “Fr. Matthew” isn’t able to leave his people or their medical facility behind, and amidst flowing lava, he must persuade others to join a risky expedition into the highlands to determine if anyone remains who needs rescuing. The film functions adequately as a showcase for Tracy and Sinatra, though it doesn't feel particularly authentic until the volcanic events near the end. While the jungle scenes avoid appearing staged with artificial plants, this isn’t a truly believable South Seas setting, and the story moves slowly at first. Grégoire Aslan, in my view, captures much of the attention available, and Jean-Pierre Aumont provides some understated visual appeal as seaplane pilot “Jacques,” but the rest of the performances and script aren't particularly strong. Some trimming could have improved the film’s tempo; ultimately, it's typical entertainment where most of the budget seemed to be spent on the leading actors rather than providing them with meaningful material. It is something you can watch, but not likely to remember for long.

Source on TMDB