SPOILER ALERT: This story contains details about the series premiere of the NBC dramedy series This Is Us.

Dan Fogelman’s This Is Us has been tugging at heartstrings ever since the first trailer was released in May, amassing a staggering more than 100 million views ahead of the show’s September debut. The dramedy’s official description:  an ensemble — some of them sharing the same birthday — whose life stories intertwine in curious ways, was designed to protect the twist at the end of the premiere. Much like the reveal at the end of the pilot for Modern Family that the characters in the individual storylines are all related, This Is Us connected married couple Rebecca (Mandy Moore) and Jack (Milo Ventimiglia), who were expecting triplets, TV actor Kevin (Justin Hartley), his twin sister Kate (Chrissy Metz), and successful businessman Randall (newly minted Emmy winner Sterling K. Brown), who was looking for his birth father. It turned out that Randall is an adopted brother to Kevin and Kate. What’s more, Rebecca and Jack are the trio’s parents as they take home the abandoned newborn Randall after one of their triplets dies in childbirth performed by a wise substitute doctor played by Gerald McRaney. In an interview with Deadline, Fogelman talks about the twist, how the multiple-timeframe stories will evolve and intersect, the enormous success of the trailer and more McRaney.

DEADLINE: What was your inspiration for the show and the twist at the end of the pilot? 
FOGELMAN: Inspiration for the show – obvious as it sounds – was basically just people. I was in my late 30s and thinking about how many friends I had, all roughly the same age, and how wildly different our lives were. Some were married with kids, other single. Others were satisfied with career paths, some making big changes. Some had lost parents, some had lost friends, some were even sick themselves- and some hadn’t been touched by any of that. So I wrote about people I knew, or better-looking versions of them. The “twist” came as I started writing, honestly. It wasn’t part of the conception.

This is Us
Courtesy of NBC

DEADLINEWhat happens next? Will Katie, Kevin and Randall interact with their parents in the past or present?
FOGELMAN: Yes, structurally the show is very much the same as the pilot – we move between the lives of all these people. But now, obviously, all the people are connected. And one of those stories is the story of the parents of the other three. And that storyline moves around in time… Our second episode picks up 8 years later (in that storyline). Their marriage is in a very different place, the kids are older. Our third episode returns them to the pilot’s time period, as they’re leaving the hospital with the babies. In the course of the first two seasons of the show, we will be unfolding the big picture story of this family and this marriage – seeing how past informs the present, etc. We even explore time before Milo and Mandy had kids. Its ambitious stuff and explaining it makes my face hurt. You kind of just have to watch and it makes sense.

DEADLINEIs Randall estranged from his adopted siblings? He seems a lot more successful than them and did not join the birthday celebration.
FOGELMAN: They live on different coasts so there is obviously more distance between them. He stayed closer to his parents while Kevin (and Kate via Kevin) chased his Hollywood dreams. They are definitely not estranged and you’ll see a lot more of them together as the season moves along. There is a particularly strong rivalry/loaded stuff between Randall and Kevin (Justin Hartley’s character).

FOGELMAN Why do you think the trailer for the show resonated with so many people?
God, I have no idea. I think NBC did a wonderful job with it. With the entire campaign. And I think it might just be the right place and time for a show like this? With everything going on in the world? Or it’s Milo’s ass. Or some combination thereof.

DEADLINE: Can we get more of Gerald McRaney?
FOGELMAN: Already did our 3rd episode. I’m also trying to convince him to become my primary care physician.