This Is Us' Logan Shroyer Teases What Happens Between Kate and Marc: It 'Changes Her Life'

A major This Is Us episode is up next for Kate Pearson — and fans should be highly concerned about her record store boss-turned-boyfriend Marc.

The bookend of the Big 3-focused trilogy series concludes on Feb. 11 when fans will dive deep into Chrissy Metz and Hannah Zeile’s character Kate by exploring how two formative relationships (her intense teenage romance with Marc and her present-day marriage to Toby) made her into the person she is today.

Audiences last saw teen Kate upset on the phone with Marc, saying, “Why are you so mad? Did I do something wrong?” Later, mom Rebecca (Mandy Moore) reached a breaking point when she told teen Kevin (Logan Shroyer): “I’m worried about Kate. And she rode off with Marc to the cabin. She just called me crying. I think she’s in trouble, Kev. We have to go get her.” Not only do they get involved, but Kevin also made an emergency call to their brother Randall, who is away at college.

“There’s always a lot going on with the Pearsons,” Shroyer, 20, tells PEOPLE, laughing.

“It’s a big deal what happens, especially in this episode and the coming episodes,” he says of Kate during her rocky week with Marc. “It definitely changes Kate’s life.”

Not only is Kevin not a fan of “greaseball” Marc, but matriarch Rebecca is also concerned. “I don’t feel comfortable with Marc,” she told Kate, who acts on the defensive.

“I wouldn’t say Kate and Kevin are super aligned right now,” Shroyer says of the twin dynamic amid her ups and downs. “Their relationship is fundamental to who they are and we start to see some more adult shoes that Kevin has to fill.”

Though Shroyer couldn’t spoil what exactly goes down, he promises: “Fans are going to go on a wild ride.”

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The storyline was previously foreshadowed when present-day Kate and Rebecca discovered old Polaroids from a past family dinner during which Marc showed up unannounced. “I wanted to believe so badly that you kids were happy, I didn’t see what was happening,” Rebecca told her daughter to which Kate unnervingly responded: “I didn’t see it either.”

The ominous cliffhanger left viewers wondering if Marc somehow does harm, psychologically, emotionally or physically, to Kate, who was 18 at the time and recovering from the trauma of her father Jack’s death.

Along with Shroyer, leading man Justin Hartley is eager for fans to find out what happens.

“I think we got a really, really special episode on our hands. I think people are going to enjoy it, the performances are off the charts,” Hartley tells PEOPLE of the episode, which he directed.

“Just seeing the talent that all these people have. They do it every week, it’s not a shock but they did bring it. We got amazing performances out of all the actors,” he says. “It was great seeing them from that perspective. I thoroughly enjoyed it. I had a blast.”

This Is Us airs Tuesdays (9 p.m. ET) on NBC.