Among the natives is Terangi (Jon Hall), newlywed to Marama (Dorothy Lamour), and who works as first mate of the tradeship Katopua, making a regular run to Tahiti. On one of those trips Terangi is ordered to leave a bar by a drunk Frenchman and the resulting fight lands him in jail for six months, unable to return to his new family. The unyielding French governor refuses to pardon him, and Turangi makes one unsuccessful escape attempt after another, only increasing his sentence and his exile.
It's a cautionary tale of race prejudice and imperialism that can only be rectified by an Act of God, and at that point second unit director Stuart Heisler takes over with a sequence of live-action, studio-bound mayhem that's horrific to watch, and head-rattlingly impressive. It's also acres above the usual "disaster movie" formula in that Ford and screenwriter Dudley Nichols take the time to actually have the audience familiar with the characters in danger, and place them in the absolute worst situation for their survival, given their traits and prejudices. It's one thing to be wary of an arbitrary natural disaster, but one should always avoid one with a sense of irony (and a sense of reckoning, as well).
Kudos to Ford for actually casting Polynesians as the natives (with the exception of Lamour—who was anything but—and Hall, who was, splitting heirs, half-Tahitian), but the rest of the cast is top-notch with Ford regular John Carradine as a sadistic guard, and an early role for the soon-to-be ubiquitous Thomas Mitchell, who makes an impression with every role. It's not Ford at his most artistic—nor, frankly, did he need to be, but he manages to make the drama on both sides of the cultural divide matter—and letting God sort it out.