It’s been an emotional roller-coaster of a season on NBC’s “This Is Us,” and all signs point to a stomach-churner of a finale. Rebecca (Mandy Moore) and Randall (Sterling K. Brown) may have finally reconnected during William’s memorial service, but Rebecca and Jack (Milo Ventimiglia)? That’s another story still waiting to be told.

The finale jumps back and forth in time, exploring how the couple first met and where they are in their marriage as of late. Rebecca’s been pursuing her singing career — and Jack’s frustrated. Which means he’s drinking again.

Fogelman calls the finale “incredibly ambitious,” for the way it jumps between time periods. “There is a scene with Milo and Mandy that I have not seen on television,” he says. “I think it’s going to rock people.”

And it all leads up to a finale that Fogelman says is “definitely the darkest place we’ve been.”

Warns Moore, “We’re going to destroy America by the end of the season. As if they don’t have enough to be upset about at this point in time anyway. But they’re going to be upset for a completely different set of reasons.”

Normally Ventimiglia’s chair is right next to Moore’s on set; the two actors talk constantly between takes. But filming the finale, he says, “I felt very removed (emotionally),” he says “We were coming together to make something great, but it didn’t feel good at all.”

The finale, says Fogelman, is what he always had in mind from the moment he pitched the show.

“From inception I knew how the season was going to end,” he says. “I knew what the final moment was going to be. Not because I’m a genius who thinks that way. I just always had a shape in my mind for what the final story was going to be. I just saw it for the first time. It’s very much what I had in my brain. Normally when you have high expectations or a plan it tends to disappoint a little bit, but it’s exactly what I hoped for.”

And while it’s going to be upsetting, he warns, “There is in the strangest way, in the end of it all, hope and optimism that is really beautiful.”

That said, Fogelman says it’s not necessarily a cliffhanger of an ending.

“At the end of our season, there are a lot of stories that leave a lot of natural progression that people will be naturally excited to go continue those stories,” he says. “I want to see that story continue now. I’m anxious for the show to come back so I can see that story continue. I don’t know if that’s a cliffhanger, but it’s the right ending for our season of television.”

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