Erika Christensen Erika Christensen

When fans saw  Parenthood last, Julia (Erika Christensen) Julia had just decided she wanted to adopt a baby, and Kristina (Monica Potter) had just learned she was pregnant. Eight months later, Kristina is about to pop, but Julia's daughter Sydney is still an only child. However, someone is about to enter Julia's life who could easily change all that.

"There's a turn of events which seems like it might be fate, and Julia has to decide whether or not she wants to be extremely inappropriate in the workplace to follow her gut and heart and her desire," Christensen tells "She'll put up a really good fight on getting what she wants and having a bigger family."

Fall Preview: Get scoop on your favorite returning shows

The event in question is someone at Julia's office who suddenly becomes pregnant and plans to give up her baby. After months of failed attempts to adopt with Joel (Sam Jaeger), Julia will slowly begin an interesting relationship with the young woman, Zoe. "She finds more of her maternal instincts throughout this whole thing, which is both wonderful and also makes the whole thing more painful because she really does have the desire to have another child," Christensen says. "[Zoe] is a little prickly. She's a smart, young thing with her guard up. I don't think that Julia sees it going that way, but she does end up feeling maternal feelings towards her."

In Julia's mind, asking if she can adopt Zoe's baby is only logical. Unfortunately, her husband doesn't see it that way. "Joel thinks she's thinks being completely irrational when she first brings it up and that's a bit of a contentious point between them, but they will resolve it," Christensen says. "Their marriage is surviving fairly well, but I think it's just on the verge. If something doesn't give soon, they probably will be quite frustrated by it."

Check out TV's best couples

One thing Julia won't have to worry about is getting daughter Sydney (Savannah Rae) on board with the idea of expanding the family. "It's going to be interesting to see how Sydney deals with it. Right now she's excited, she wants a little brother — they want a boy," she says. "She may discover that she doesn't want a little brother once she gets one, but at this point, she's open to the idea."

Outside of the Braverman-Graham household, Julia's struggle to adopt will bring her closer to her older sister, Sarah (Lauren Graham), a duo that has yet to be deeply explored in the large ensemble cast. "Julia and Sarah have been brought a little bit closer in their adulthood by each of their troubles. They do seem to be able to confide in each other a little bit, which I think is new for them, and I like that a lot," Christensen says. "They're there for each other."

Parenthood's Jason Katims on Crosby and Jasmine's separation, Jason Ritter's extended stay

Julia will also be getting an earful (as per usual) from Braverman family patriarch Zeek (Craig T. Nelson), who's more than happy to share his thoughts on Julia and Joel's life-changing decision, for better and for worse. "He's not always the most considerate, but he's got such a good heart and it comes from a really good place when he tells you you're being an idiot so he's sometimes scary to tell things to because you don't want to go through whatever his opinion might be on it," Christensen says. "He has an insight, but it can be rough."

Out of everyone in the extended Braverman clan, the biggest question is how Julia and Kristina's friendship will fare in the wake of Julia's inability to get pregnant and Kristina's unexpected pregnancy. Christensen says Julia won't hold anything against her sister-in-law, but says there will be moments of hurt feelings. "There's that longing, that wistful feeling of, 'Wow, this is really happening for this person and I want it to be me,'" she says. "The last scene we shot was everybody meeting the baby after she's born and Julia is the first person to ask if she can hold the baby. The baby and Julia connect."

Parenthood Season 3: "Heartbreaking" baby drama ahead for the Bravermans

But considering how timely and costly and complicated adoptions can be, have Julia and Joel braced themselves for the possibility that it may not happen for them? Christensen admits she would be intrigued to see Julia cope with another detour in her road to motherhood the second time around. "Julia is an extremely tenacious person so I think she will come up with a Plan B or a Plan C if things don't work out," she says. "What will be interesting for me is if she finally decides to abandon that pursuit and do something else entirely."

Parenthood returns on Tuesday, Sept. 13 at 10/9c on NBC.