SPOILER ALERT: This story includes details about the Dec. 6 fall finale of NBC’s This Is Us.

Dan Fogelman’s fall breakout This Is Us stayed true to form in its fall finale tonight, mixing heart-warming and heart-wrenching moments in an episode that also managed to mix both Christmas and Hanukkah celebrations. Titled “Last Christmas”, the finale, written by co-showrunner Don Todd and directed by Helen Hunt, is set on Christmas Eve in two time periods — present and back when Kate, Kevin and Randall were 10-11 — a device the series also used for its Thanksgiving episode two weeks ago.

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“Last Christmas” is framed by mom Rebecca’s (Mandy Moore) words assuring younger Kate that “nothing bad happens on Christmas Eve” as the girl is wheeled into surgery after her appendix bursts. There is obviously no suspense over Kate’s fate as she is alive (though not quite well) in 2016, as she continues to struggle with weight, though there are a slew of touch-and-go moments in the episode, with Dr. K facing a very risky life-saving operation, Randall (Sterling K. Brown) bumping into a co-worker who is about to jump off a building, and dying William contemplating his likely last Christmas as he rekindles an old romance with a guy he had pushed away.

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The episode manages to live up to Rebecca’s “nothing bad can happen” adage until the last seconds when Toby (Chris Sullivan), who had flown in from California to win Kate (Chrissy Metz) back, collapses just as the entire Pearson clan had gathered, enjoying spending Christmas Eve together.

In an interview with Deadline, Fogelman addresses the dramatic cliffhanger and its possible outcome, as well as the impact of tonight’s revelation that William is gay. Fogelman also teases future episodes that would feature William’s mom and other birth relatives, more play with time and more Dr. K.

DEADLINE: What happened to Toby and will he make it?

FOGELMAN: Well you’re gonna have to wait 3.5 weeks or so to find out what happened to Toby. Hopefully by now we’ve shown that we’re not scared to make a big choice. That said: the show has an optimistic underbelly. So I guess you could say there’s an argument that could be made both for Toby “making it” and “not making it.”

DEADLINE: The title of the episode is Last Christmas. Does that refer to William, Toby or someone else?

FOGELMAN: I believe in the first draft, Don Todd – who wrote the fantastic script – had scripted “Last Christmas” by Wham as the song that opens the episode in the ’80s. In the edit it didn’t feel quite right and felt better to open and close with the Sufjan Stevens Christmas song. But the title held – I like how it refers to previous holidays (as in “do you remember last Christmas”) but also – in the end – carries a slightly ominous tone.

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DEADLINE: With Dr. K, Randall’s co-worker and William all being on the brink of death in the episode, why did you decide to go with Toby for the dramatic life-or-death cliffhanger?

FOGELMAN: I think it’s simply a case of life not always serving you exactly what you expect – as the older guys battle cancer and life-threatening surgery, sometimes it can be the young, big guy with the bad eating habits dropping out of nowhere.

DEADLINE: How did the idea to bring Gerald McRaney’s Dr. K back for the Christmas episode come about and will we see him again?

FOGELMAN: Gerald is so wonderful in the pilot, we always want to bring him back whenever we, organically, can. It’s hard though, because he’s their doctor and you don’t exactly go to the doctor every day (nor do you want Dr. K peeking over the fence every episode after he moves in next door). But this episode lent to it… we also have a LOT of Dr. K in the next two episodes after we return from the break. One episode I am particularly excited about delves (partially) into what Dr. K was doing in the 24 hours before he got the call to fill in and deliver the triplets for Jack and Rebecca.

DEADLINE: How will the revelation of William being gay and the introduction of his boyfriend change the dynamic of his relationship with his son and his family?

FOGELMAN: It’s a big story we explore in the next episode of the show when we return. It’s not that William is gay (or bi) that throws Randall, particularly (although it does shock the hell out of him). It’s that suddenly he’s losing time with his father (and there may not be much time left) to another person. It’s a very sweet father-son story.

DEADLINE: Have Randall and Rebecca patched things up? Has he forgiven her?

FOGELMAN: I think you see a few small moves at the end of the episode. We had talked – originally – about Randall fully forgiving his mother in this episode. But it didn’t quite feel real, that someone just forgives something that big – in full – just like that. It feels like Randall is a good enough person – and he and his mother are close enough – that forgiveness and understanding is in sight, but I think it’s gonna take a minute to reach it completely.

DEADLINE: Will we find out more about Randall’s biological mother beyond the glimpses we got of her on the bus early in the series?

FOGELMAN: We have a big episode coming that focuses a lot on William and William’s backstory. Not only do we see more of Randall’s mom, but also his grandparents.

DEADLINE: Will the show visit another time period this season, perhaps with Kate, Kevin and Randall as 20-somethings?

FOGELMAN: There are quite a few more time periods in the rest of the season. We’re taking great care to keep the audience on their toes without making it too abstract or hard to follow. So we’re careful how we switch periods and in what order we do so. Thank god for Milo’s malleable facial hair, is all I can say.

DEADLINE: What did Helen Hunt bring to the table as director of the fall finale, is there any element that was her idea?

FOGELMAN: She did a wonderful job. She’s a very precise director – she does the work, does the prep, there was very little left to chance in filming. Her cut was truly excellent – she trimmed all the fat and did so much of the work for me. Don wrote a beautiful script and she let the words do the work, and made it all sing. One of my favorite things we’ve done was the final 5-minute montage that ends the episode. Basically: we had the whole cast in one room for the first time, and just gave Helen a list of ideas and told her to just shoot. She put it to the Sufjan song and it’s just beautiful. To me it really feels like you’re watching a real, loving family hang on Christmas Eve – which is, of course, the point.

DEADLINE: Where is the series going from here, what is in store for the second half of the season?

FOGELMAN: I’m really excited about where we’re going. People have liked the show, and by whatever metrics we measure these things it seems to be succeeding. That creates confidence, which allows for bold choices. We have a bunch of episodes coming that focus on particular characters and storylines, which I love for this show. As I mentioned we play more with time – changing time periods, seeing Jack and Rebecca in various time periods (even before they met), and completing a lot of our season 1 storylines that we’ve established. Hopefully it all won’t go to sh*t. I don’t think it will.