Fingernails, a sci-fi romcom coming to Apple TV Plus from director Christos Nikou, imagines a future where one very specific technology has changed the world. In this timeline, scientists have figured out how to conclusively determine if two people are in love. This upends relationships as we know them, with couples sticking steadfastly to the results of the test; if they get a negative result, they end up splitting up. It’s a cute conceit for exploring the ways relationships can grow stale or change over time, and Fingernails builds on that with its darkly comedic vibe. It also has a surprising amount of body horror — the nature of which you might be able to glean from the title.
The film centers on Anna (Jessie Buckley), a teacher who…