Willa Fitzgerald Willa Fitzgerald

[WARNING: The following story contains spoilers from Tuesday's episode of Royal Pains. Read at your own risk!]

The Lawson family grew by one on Tuesday's episode of Royal Pains, and we're not talking about a baby on the way for Evan and Paige. After arriving in the Hamptons last week, and promptly kicked to the curb when Divya (Reshma Shetty) mistakenly assumed she was a stalker, the mysterious Emma (Willa Fitzgerald) finally revealed her true motives: She traveled to the Hamptons looking for her father, Eddie R. Lawson (Henry Winkler), which also makes her the half-sister(!) of Hank (Mark Feuerstein) and Evan (Paulo Costanzo).

"We've always had, from the beginning, family as the major theme of our show," executive producer Michael Rauch tells TVGuide.com. "We felt that the notion of bringing in not just a new character, but a new character who was linked to Hank, Evan and Eddie, obviously did not just fit into our series theme, but gave us an opportunity to introduce new dynamics amongst the characters."

Rauch, along with co-creator and executive producer Andrew Lenchewski, spoke with TVGuide.com exclusively about the decision behind Tuesday's big reveal, Eddie's road to redemption with his new offspring and whether Emma can really be trusted.

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How did the idea come about to introduce a new family member into the Lawson clan?
Michael Rauch:
The idea actually came because one of the executives at USA who is very close to the show told us a story about how when he was in his late 20s, early 30s, he discovered that he had a long-lost brother and it triggered something for us in terms of the interesting human dynamic of that. We knew him, but we never knew that about him so we started to ask more questions about what that was like to find that out, and what made that made him think about himself and his past and his family. It got more and more interesting to us.

How did this executive react when he heard you were using this story for the show?
Andrew Lenchewski: He's been one of our story whisperers. The idea to make Divya pregnant came from him, the idea to introduce, a few seasons back, a couple of female lesbian characters as Libby's moms was his idea so he's got a great track record with us. ... He was a really great sounding board for us throughout the process and he really invested in and embraced it.

Was it always a plan to have it be a younger half-sister or there were other options you explored?
It was always going to be a younger sibling and we spent a little bit of time talking about it being a brother. We landed somewhat quickly on it being a younger sister, but we spent an inordinate amount of time deliberating about how old she should be. One day in the writer's room, we kid you not, we spent six hours talking about whether she should be 16 or 17 and what the difference was between those two ages and of course there's a world of difference. We've had this longing to bring back a character who evokes what Tucker, played by Ezra Miller, brought to the show in the first couple of seasons. ... Ultimately what it came down to was we wanted a character who was old enough to cause trouble, but young enough to be impressionable so there was room in her life for Hank and Evan and the rest of the HankMed family to make a difference in her world.

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What kind of impact will they have on her? And vice versa, what kind of impact will her arrival have on Hank and Evan?
To bring in a new character who is not just introduced to a new world, but is introduced as a family member and someone they didn't know about, blows everything up. Evan and Hank, when they first discover this, are in a state of shock because it obviously has a major impact on what they thought was their family. It also allows us to see how they help Emma become more comfortable in the world of the Hamptons. She's a fish out of water there. So as they gradually begin to learn to trust each other, both operating from a place of being not quite sure if they're being told the truth, this enables Hank and Evan to change because of Emma's presence and then Emma also to change because she now has these two older brothers who care a lot about her and love her.

Emma went to great lengths to lie to Hank, Evan and everyone about her life. Now that she has told the truth, can the Lawsons really trust her? Or should they still be worried about any other tricks up her sleeve?
Exactly. That's what we want the audience to be asking all season long. The original impetus for bringing in a character like this into the show early in the season is we wanted a character to come and really shake things up. With Emma's backstory, we found an organic way to explain why she has the psychology that she has. She's had plenty of reasons not to trust people. Her mom got into trouble with card counting and stuff like that, and some of that has potentially rubbed off on Emma. This is a girl who wants to be a better person, is trying to do the right thing, but she's saddled by some of the baggage from her childhood. And so we're not going to be sure from episode to episode whether she's coming clean or whether she's pulling something else out of her bag of tricks. Hopefully by the end of the season, Hank and Evan will help her find some moral clarity.

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Obviously Eddie was not very receptive to Emma's arrival at the end of the episode. What can you tease about his relationship with her mother, Meredith, and how he'll come to accept Emma?
This is a surprise to him on many levels. There were untruths that were told by Emma's mom that Eddie gradually finds out, as do we, which changes the dynamic. Unlike with Evan and Hank when Eddie took off basically at the age where Emma is now, and missed them going from teens to young adults, he's now present for that and wants desperately to make up for that. It gives him the opportunity to right some wrongs that he made with Evan and Hank.

Will that have any effects on his relationship with Hank and Evan?
It's going to bring back up echoes of a lot of that pain, but it's also going to be a new chapter in the Eddie-Hank-Evan dynamic because they're going to watch Eddie go through these stages of shame and fear and acceptance, and ultimately love, and they're going to be a big support system for him as he goes through that process. This time around, they're going to be much more optimistic about his humanity than when he reappeared in their lives in Season 2. They believe him when he tells them that he didn't know anything about Emma and they believe him when he says that he wants to raise this girl and make her a part of the family.

How will Emma integrate herself into the Hamptons community?
Obviously there is a tradition in television of characters like this being introduced as a show starts to mature. What we think we can do uniquely in our show is tell that story with the Hamptons being a character in the story. Part of what's going to happen in Emma's journey is she is going to arrive in the Hamptons and be completely in awe of this world. It's unlike anything she's ever seen, anything she's ever experienced and she's going to be seduced by it. So at times, she may start to seem to Hank and Evan that she's falling in with the crowd, that she's becoming a little too aspirational and chasing the glitz and the glamour and the money. She's going to get involved with a very popular blog called Snark Hamptons and that's going to become a big part of her story line. ... She's going to slowly start to integrate herself for better and for worse into this world.

Royal Pains airs Tuesdays at 9/8c on USA. What did you think of Tuesday's surprise twist? Do you trust Emma? Watch the Season 6 premiere here.