Star-crossed lovers are always ripe for the big screen — a fact understood well by filmmakers James Floyd and Sally El Hosaini with the vibrant if familiar Unicorns. Mechanic-meets-drag-queen isn’t yet part of the genre’s vernacular, but the film makes a fine case for this new couple to become part of the canon.

The tragic lovers here are mechanic and single dad Luke (Ben Hardy) and drag queen Aysha (Jason Patel). They meet in a club — a wordless, intoxicating encounter — before Luke notices the Adam’s apple of his object of affection and things get complicated. Perhaps this kind of point-blank prejudice feels a few years old in cinema, but it’s no less tragic in the real world.

Luke and Aysha individually are more compelling than the sum of their parts.

The film explores self-expression and the definition of family protection carefully, looking at what it means to...