That's what writer-directors Michael and Peter Spierig (they’re twins) and star Ethan Hawke kept in mind as they spoke with the S.F. Examiner by phone recently: Nobody wants to give away anything good.
"We didn't know if we could pull it off," says Michael. "We didn't even know first day of shooting. It was a terrifying prospect. We've never been in that kind of position before." The Spierigs’ previous films include fun, fairly straight-ahead genre pictures – the zombie movie "Undead" (2005) and the vampire movie "Daybreakers" (2010), the latter starring Hawke.
In “Predestination,” opening Jan. 9, they have two characters with no names that are required to pull off multiple tasks. Hawke plays a Temporal Agent, a traveler who jumps back and forth in time. His ultimate goal is to stop a killer known as the "Fizzle Bomber."
The impressive young Australian actor Sarah Snook ("Jessabelle") has a much harder job, going through a complete physical transformation during the story.
"If Sarah's character doesn't work, the whole thing topples," says Michael. "She found the balance of both sides. She was so wonderful."
Hawke likes thinking about the story's deeper meanings, questions of whether aspects of life are inevitable.
"Things happen in life and 20 years later they seem inevitable," he says. "'If only I'd said this...' But when you're living the day to day moments, it almost seems like everything hangs on a razor's edge."
He continues. "That's what I love about science fiction at its best. You can really talk about serious philosophic ideas, without seeming like some bulls--- professor."
As an actor, however, he found "endlessly interesting" challenges in relatively simple setups. For much of the movie, the two actors sit in a bar and talk. But because of the time travel aspect, Hawke's character has extra knowledge and must decide how to use it.
"There are so many things that are unique," Hawke says. "This movie is so much about identity. Who are we? And then you have two identical twins talking to you. It's kind of intense."
What is the on-set work dynamic like between the brothers and Hawke?
"One brother tells you to pick up the paces, and the other tells you to slow down," Hawke laughs. "It's wonderful. We just bicker with each other and then we get to do it the way I want to."
IF YOU GO
Starring: Ethan Hawke, Sarah Snook, Noah Taylor
Written and directed by: Michael Spierig, Peter Spierig
Running time 1 hour, 37 minutes