Like everything else by the singular writer-director Leos Carax, Holy Motors (which opens Friday at the Music Box) is so intensely personal that uninitiated viewers might wish they were provided footnotes before going in. To cite just one of the film’s cryptic gestures, between the final shot and the end credits, Carax briefly fills the screen with a photograph identified by only a few words in Cyrillic. The photograph is of Yekaterina Golubeva, the Russian actress who played a leading role in Carax’s previous feature, Pola X (1999), and appeared in movies by Claire Denis and Bruno Dumont. Golubeva and Carax had lived together for several years and were raising a child when she died under mysterious circumstances last year. While Holy Motors is generally playful in its storytelling—the dreamlike plot concerns a shapeshifting figure named Monsieur Oscar (Carax’s real middle name, incidentally) who assumes about a dozen different identities over the course of a day—its tone becomes increasingly morbid as it goes along. If you’re unfamiliar with the director’s biography, this unusual progression just might seem perverse.