This Is Us: Mandy Moore Foreshadows 'a Lot of Obstacles' in Rebecca and Jack's Early Romance

This Is Us season 4 premiered with many new faces and storylines for the Pearson family in the past, present and future.

Tueday’s episode included the Big 3’s birthday, with the siblings turning 39 this year. But it was a milestone in the ’70s that caught the most attention: Rebecca’s big step of introducing Jack to her parents, who were less than enthusiastic about him following the couple’s cross-country road trip to Los Angeles.

Viewers got a flashback glimpse into the early days of then-Rebecca Malone and Jack’s courtship, as their fourth date was centered around a tense dinner at the country club with her father Dave (Tim Matheson) and her judgmental — and rather racist — mother Janet (Elizabeth Perkins), who fans first met in season 2.

“This season we’ve only started exploring Rebecca when she knows Jack,” Mandy Moore tells PEOPLE exclusively. “That’s the time period I’m really interested in: their initial meet-cute, date and the road trip out to California. Then the immediate aftermath of them getting back from that trip, home in Pittsburgh, meeting her parents and figuring out how they fit into each other’s lives back at home.”

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Fresh off his return from combat in the Vietnam War, Jack is struggling financially — he’s crashing on a friend’s couch and without a job — but needs to wear a sport coat for the dinner. So, he visits the local clothing store, where he is helped by salesman Miguel (Jon Huertas, surprise!) for a meet-cute that ends with Jack renting a navy blazer for free as long as he doesn’t take off the tag.

Rebecca had warned her parents not to discuss Vietnam, at the dinner, but her father kicks off the evening with his opinions on the war. Then, Jack wins Rebecca’s heart over when he honestly and charismatically speaks about the “death” of brother Nicky and the realities of war. However, during a celebratory sip of his beer, the tag of Jack’s sport coat peeks out of his sleeve and catches her watchful father’s eye.

“I’m really curious about that time period because there are a lot of obstacles that I didn’t see coming initially,” Moore, 35, tells PEOPLE.

The Emmy-nominee also foreshadows: “You sort of think like, ‘Oh, here are these soulmates, these two people that were meant to be together.’ But I love that last season showed that their love story wasn’t a straight line. It kind of deviated in ways that are a bit unexpected.”

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One of those obstacles could be Matheson’s character interjecting the future of Rebecca and Jack’s romance. “I want more for her than you can offer Jack. I will do everything I can to stop this,” the protective patriarch said after the dinner.

Moore adds, “I’m excited and eager to continue exploring their love story and the obstacles that they’re going to find along the way.”

Actors Jennifer Morrison (who plays military veteran Cassidy Sharp), Asante Blackk (young father Malik), Marsha Stephanie Blake (Malik’s mom), Omar Epps (Malik’s dad), Bahara Golestani, Julian Silva, Auden Thornton (expectant mom Lucy) and Nick Wechsler (Cassidy’s husband Ryan) made their This Is Us debuts in the premiere, too. 

Did you know the last name of @jenmorrisonlive character on @NBCThisisUs is #Marine Staff Sgt. #Cassidy Sharp. The last name is actually an homage to a Marine I served with in combat. @USMC Lance Cpl. Charles S. Sharp, died in combat on July 2, 2009. https://t.co/g9hLAIIbED pic.twitter.com/WTP1zC1Wwc

— James LaPorta (@JimLaPorta) September 25, 2019

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RELATED: This Is Us Star Chris Sullivan Promises ‘Completely Unexpected’ Season 4

View this post on Instagram Tonight’s the night of my television debut! Check out my story later this evening to see which network to watch. Thanks

A post shared by BLAKE STADNIK (@blakestadnik) on Sep 24, 2019 at 12:36pm PDT

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Malik is 16! still definitely shouldn’t be having a kid but…yeah https://t.co/Yb023jD8rS

— Asante Blackk (@AsanteBlackk) September 25, 2019

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And fans were introduced to actor Blake Stadnik, who is legally blind, as Jack Damon, the adult son of Kate (Chrissy Metz) and Toby (Chris Sullivan), who finds success in music — surely to the great pride of his grandmother Rebecca.

Stadnik’s character returns this season in another flashforward look, according to creator Dan Fogelman.

Still to make their big cameos this season are director M. Night Shyamalan and actor Timothy Omundson.

This Is Us airs on Tuesdays at 9 p.m. on NBC.