Justin Hartley and His This Is Us Costars Tease Season 4: 'It's Going to Be a Split Reaction'

Happy This Is Us premiere day!

The hit NBC series returns Tuesday, two months after the season 4 winter finale. And according to its stars, this new batch of episodes is full of twists and turns.

Speaking to PEOPLE at the Critics’ Choice Awards on Sunday, Asante Blackk, Justin Hartley and Susan Kelechi Watson teased what’s ahead as the show returns from hiatus.

“It’s going to go to a place that a lot of people will be satisfied with, but a lot of people might be unsatisfied with,” said Blackk, 18. “So it’s going to be a very, very split reaction. But This Is Us always tricks us, always adds in those tricks and surprises at the end, so without trying to give too much away, you guys are in for a treat.”

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Hartley, 42, said his character Kevin is at a major turning point after a flash-forward in the midseason finale revealed that his dreams of becoming a father are coming true, though he and his brother Randall (Sterling K. Brown) are estranged.

“We basically find Kevin in a situation where something has gone on in his life, something has happened recently, that he’s dealing with that sort of brings up a lot of unfinished business in his life,” he said. “Things that are maybe really close to him, maybe close enough to touch, and he’s got to sort of deal with it in a real way.”

“It’s pretty heartbreaking, but I also think it’s a cleansing moment for Kevin — a real hurdle that he’s able to get over, and sort of a color to him that we haven’t seen before,” he added. “And an acceptance that maybe you don’t always get what you want, even if you really deserve it.”

As for Watson, 38, who plays Randall’s wife Beth?

“[This season is] about Beth and Randall kind of managing what’s going on with him, with his mental health,” she explained. “And how we can still both manage everything that’s going on in our household without her having to take on the majority of it, because he has to deal with his anxiety and things like that.”

This Is Us returns Tuesday at 9 p.m. ET on NBC.