I finally found an anthology containing “Random Quest,” the John Wyndham short story that became the SF love story Quest for Love. And having rewatched a fairly faithful adaptation from the BBC (also called “Random Quest”) I’ve got to say that the unfaithful version is an improvement.
The short story is “drawing room science fiction”—the kind where the protagonists sit around in the drawing room over drinks and a pipe and discuss the mind-blowing implications of what’s been going on. In this case, a doctor grills a young physicist on why he’s so determined to find a member of the doctor’s family who doesn’t exist (the doctor’s deductions are the best part of this). The physicist explains how he was transported into an alt.world where his counterpart was a successful novelist and a jerk, fell in love with his counterpart’s wife—who was delighted her husband had stopped being a jerk—and then got yanked back to his own world. Now he wants to find the woman’s counterpart, but the family insists such a woman was never born. The doctor points out that even if she existed, she wouldn’t be the same woman as the physicist met—an unusually logical point in Exact Double stories of this sort, but then they ignore it in the conclusion (why yes, he did find the woman).
The BBC production adapts this quite faithfully. Quest for Love does not, adding in lots of melodrama, starting with the counterpart being a much bigger douchebag and the wife refusing to believe in his apparent reform. That gives the protagonist a lot more of a challenge. And then it turns out she’s terminal, so his search for her counterpart in this world is urgent: our timeline has a medical treatment that can save her, but only if he finds her soon enough. It’s a lot more entertaining, though as I said in my first post, you need a high tolerance for good quality schmaltz.
Not sticking to the source was definitely a wise move in this case.