Here, we have a high-concept, low-budget and entertainingly effective existential puzzle that will reward thinking moviegoers with attention spans longer than one movie set piece. Call this one brain candy as opposed to the usual sci-fi eye candy.

It’s a complex, paradoxical, time-travel mind-messer that mixes elements of Looper, Memento and Back to the Future to create something fairly original in a byzantine, snake-devouring-itself plot structure. It’s based on the 1959 short story “All You Zombies” by Robert Heinlein, adapted and directed by Australia’s twin Spierig brothers (Daybreakers, Undead).

Ethan Hawke is the main character, a sort of time cop chasing an elusive terrorist. While working undercover in another time, he happens upon a fellow whose backstory is a real mind- (not to mention gender-) bender. The fellow in question is played by Sarah Snook in a knockout performance, showing in one movie more range than most actors do in an entire career.

Due to the tricky nature of the movie, I can’t really tell you much more for fear of spoiling some of the surprises, of which there are many. But this one will play with your brain while it touches your heart. (97 min)