★★★★☆

Whenever a movie about time travel is released, its logic quickly falls prey to scientific criticism. Can two versions of the same material self exist simultaneously? Were things always meant to happen a certain way, or is there room for deviation? How would a time machine even work anyway? The new sci-fi thriller “Predestination” boldly answers none of these questions.

Written and directed by the Spierig brothers, this film is not interested in working through the scientific mumbo jumbo of time travel. You will not find the latest physics theories carefully woven into the mix, as current genre movies like “Interstellar” try so hard to do. Instead, “Predestination” relies on a plot fueled purely by the emotional ties of its characters and their shocking revelations, and this aspect of the movie makes it such a wild ride.

The film is closely based on the 1959 short story “—All You Zombies—” by Robert A. Heinlein with one or two exceptions. A time travel agent named John (Ethan Hawke) recruits a seemingly random man from the past to venture even further back in time in an attempt to stop a domestic terrorist known as the Fizzle Bomber. A terrible New York bombing is destined to take place, and only John and his companion can stop it before it happens.

While that overarching action builds up some of the anticipation and sets the pace for later action scenes, there is a more intricate and poignant plot that underlies the film. John and the mystery man first meet in a bar room setting, where the man reveals himself to be a downcast columnist known as the “Unmarried Mother.” Once female himself, the writer begins to tell John of his transformative experiences being a hermaphrodite.

Told in a series of flashbacks, this flip-flopping identity crisis pulls the heartstrings of the audience and gives “Predestination” its distinct flare. Sarah Snook’s performance as the Unmarried Mother at times may be uncomfortable because of the nature of what her character goes through. She was recruited and later rejected from a program that provides comfort women for men in space and undergoing extensive sex-change operations just after giving birth. However, Snook carries these difficulties with grace. The dual-sided sexuality of her character allows her to flex all of her acting skills, and she creates a person whose touching resilience only builds as the movie progresses.

Snook completely steals the spotlight from her better-known peer Hawke with her character’s subtle awkwardness, and she adds depth to a plot that depends upon its character development. During this part of the movie the sci-fi remains at the fringes of the story, and without subtle reminders of what’s to come such as the repeated mention of the elusive Space Corps program, it would be easy to label it a sad yet realistic drama.

And just when you start to wonder how all of this information could possibly be connected to the problem with the Fizzle Bomber that is when the time travel paradoxes begin.

With a guitar-shaped time travel kit as wonder-worthy and inconspicuous as the famous Harry Potter time-turner, John and the Unmarried Mother finally travel back in time to stop the terrorist. The sci-fi aspect of the movie has at last hijacked the plot, and it is filled with uncanny twists as layered and mind-boggling as those in “Inception.”

There are moments when logic seems to break and thought-provoking ideas come across in pretty corny lines (The whole “what came first, the chicken or the egg?” scenario comes up sporadically), yet the film’s social dynamics leave viewers pondering after leaving the theater. The Unmarried Mother’s identity crisis is destined to strikes timely chords in controversial issues surrounding sexuality and gender orientation. Its science may be filled with loopholes, but the true draw of “Predestination” comes from its character development rather than its sci-fi foundations.