The final three episodes of the season will focus on Kate and Toby's bachelorette and bachelor parties in Las Vegas and their wedding, as well as a special backstory episode for Randall and Beth's foster daughter, Deja.

NBC's This Is Us spent nearly two seasons leading up to the death of patriarch Jack Pearson (Milo Ventimiglia). But now that the mystery of his death has been revealed, the Dan Fogelman-created family drama will focus on other eras in the Pearson family's lives for the remaining three episodes of season two.

Executive producer Isaac Aptaker, co-showrunner alongside Elizabeth Berger and Fogelman, told The Hollywood Reporter that that the past two episodes of the series — which focused on Jack's death and funeral — were "perhaps the two saddest episodes we've ever done on this show, so it was very important to us to return with something a bit lighter and a bit more celebratory."

And that's exactly what the next episode will entail when the series returns Tuesday from its Olympics-fueled break: the Pearson siblings and their significant others head to Las Vegas for Kate (Chrissy Metz) and Toby's (Chris Sullivan) joint bachelor and bachelorette party.

"We're going to Vegas, so things definitely get a little crazy," Aptaker said. "Of course, it is This is Us, so there's some family dynamics and we do get to an unexpected place like usual. But overall, the episode has a fun-ness to it and it has a lightheartedness to it that we have not had in our last two as we said goodbye to Jack. Toby and Kate are going to Vegas and having a joint bachelor/bachelorette party. He's very, very excited to kind of bro down with Kevin [Justin Hartley] and Randall [Sterling K. Brown] for the weekend, and Kate is actually a little bit trepidatious to spend the weekend with Beth [Susan Kelechi Watson] because the two of them aren't the closest of sister-in-laws and honestly don't really know us each other all that well, so she has a bit of anxiety about this weekend with her sister-in-law."

The flashback storyline will move from the teen siblings to their slightly younger versions, as the kids plan a big anniversary party for their parents Rebecca (Mandy Moore) and Jack.

"We're jumping away from [the time period surrounding Jack's death] for a bit," Aptaker said, "so when we come back on Tuesday we're doing a fun, romantic story set in the 10-year-old time period all about celebrating Jack and Rebecca's wedding anniversary and what happens when our little Big Three decide to jump in and try to throw them an anniversary party for the ages — which of course never goes well when it's being spearheaded by a few elementary school kids."

The following week will focus on Randall and Beth's foster daughter, Deja (Lyric Ross), and her backstory before moving in to the Pearson house.

"It's really unexpected and special," Aptaker said. "We're going to do a deep dive and explore Deja because we've gotten to know her through the context of Beth and Randall, but if you think about it we really know very little about what her situation was before she wound up in their house or once she was removed from it. We're looking at the flip side of our story as in what things have been like for Deja and what led to her winding up in the Pearsons' lives."

The week after — the season two finale — will see the entire family gather at the Pearson family cabin for Kate and Toby's wedding.

"It's always so much fun for us whenever we can have all of our characters in one place, which is a little rare because of the nature of the show and everyone living on different coasts," Aptaker said.

The episodes will also include more flashbacks to Jack's past, including his time in Vietnam, and maybe even some flash-forwards. The end of the Super Bowl episode saw Randall in the future with his grown-up daughter Tess, and Aptaker promised that the show will visit other characters in the future as well.

"It's not a one-time thing," he said. "We didn't just do that to be splashy during the Super Bowl episode. Since the beginning that's been something we've known we were going to get to in the show. We had a lot of story we wanted to tell before we got there, but now that we've visited that time, nothing's off the table and we will certainly be returning there in the future."

In fact, now the present-day storylines can inform the future, much like the past storylines inform the present.

"It's so much fun for us as writers and storytellers, getting to imagine what these people are up to 10-15 years in the future," Aptaker said. "We haven't put an exact year on it. It's just like the possibilities are endless. It opens up the show in a way. It adds this whole new color and dynamic to the show because all of a sudden what [Randall] does at 37, we can see how it affects what the world is like 15 years later. We're very excited; it's a new toy for us to play with and we can't wait."

The final three episodes of the season are hopefully leading toward a happier, more uplifting conclusion for a season that was so focused on death and grief. Aptaker said the finale sees the Pearson siblings finally beginning to move on from the intense grief they've experienced surrounding their father's death.

"They're always going to miss him, they're always going to mourn him, but looking forward they're hopefully going to be doing it in a more healthy way," he said. "I think there's a real excitement for the places these characters can get to in season three, really for Kevin and Kate. This season has been so marked by them trying to find closure on their relationship with their father. And then there's a couple moments at the end of the [finale] that are definitely 'whoa' moments that I can't talk about at all, unfortunately, but are going to get people very excited for what's next."

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