Mysteries big and small pervade NBC’s new fantasy drama "Manifest” (Mondays, 10 ET/PT), not least of which is the planeload of passengers that went missing for five and a half years but didn't age a day when they finally touched down.

What’s clearer is the show’s core theme of second chances, redemption and the religious and scientific implications of one seriously phenomenal situation.

“That debate is as old as time itself. It's really the ultimate debate in human history: faith vs. science,” says “Manifest” creator Jeff Rake. “I challenge myself in every episode to tell the story of what would really happen if something this extraordinary ever occurred.”

Last week’s high-rated premiere (16.1 million viewers through Thursday and counting) introduced the central group of characters whose lives were changed by Montego Air Flight 828. Heading home to New York City from Jamaica, siblings Michaela (Melissa Roxburgh) and Ben Stone (Josh Dallas) – along with Ben’s leukemia-stricken 10-year-old son Cal (Jack Messina) - decided to take a later flight than the rest of their family.

Now, since all the passengers were presumed dead, Michaela’s boyfriend and fellow cop (J.R. Ramirez) is married to her best friend, Ben’s wife Grace (Athena Karkanis) is torn between her husband and a mystery relationship, and Ben also feels guilt about missing the formative years of daughter Olive (Luna Blaise).

Oscar-winning filmmaker Robert Zemeckis signed on as executive producer because “Manifest” was an incredibly compelling “What if…?” story about "the mysteries that we all experience,” he says. “It's a metaphor that allows us to sort out these complex issues, of course which may or may not ever be answered.”

Michaela is a “tragic character” who’s walked away from her faith, and viewers “meet her after she'd fallen a long way down,” Roxburgh says. But “she's got this glimmer of hope in her eye. She's kind of looking at it like, ‘Maybe we're being called back for a spiritual reason.’ ”

Dallas believes in “a higher power that's guiding this whole crazy world” and enjoys playing his opposite: Ben “deals in absolutes” as a man of math and science.

“Is what happened to them something that can be explained by science, or is it something much more spiritual, or does it somehow lend itself to both?” Dallas says. “Who knows, maybe Ben might be swayed.”

While the big question at the heart of “Manifest” is a long game, Rake promises a “major mythology reveal” halfway through the first season that will be “surprising and satisfying.” But throughout, small clues will peel layers of the onion.

Last week's premiere showed a psychic connection between passengers. Michaela and Ben heard the same voice, which led them to save two kidnapped girls, and some of the returned passengers had a shared vision that brought them all back to the plane, which then exploded. This week, a musical theme connects Ben with a fellow passenger, street violinist Radd (Curtiss Cook), who needs to help his son.

Michaela's mother died while she was missing, and she embraces her mom’s mantra “All things work together for good,” taken from Romans 8:28 – a passage Michaela notices in a church that also mentions those “who have been called.”

Characters with “callings” prove a major aspect of “Manifest” going forward, though Roxburgh warns, “It's not always going to pan out for (Michaela). It's not always going to support her. It's going to bite her in the (butt) sometimes. We get to see her figure out if she should trust this thing.”