Calista Flockhart, Balthazar Getty and Rachel Griffiths in Brothers & Sisters by Scott Garfield/ABC Calista Flockhart, Balthazar Getty and Rachel Griffiths in Brothers & Sisters by Scott Garfield/ABC

The Walkers are back this Sunday (at 10 pm/ET, on ABC) with the first of four new episodes, and it sounds like they're bringing major drama with them. "Oh, there is such a reveal coming," teases exec producer Alison Schapker. "Involving the whole family."

But before we get to any shockers, there are a few matters that need to be addressed, including Nora's romance with the D.C.-based Isaac. "It's not so much [about] Isaac as it is Nora soul-searching about whether she's ready to be in another couple," says Schapker.

And speaking of couples, politics won't be the only thing testing Robert and Kitty when they begin in-vitro treatments, while the reconciled Kevin and Scotty, in Schapker's words, "come to terms with being in a serious relationship."

As for the show's resident non-couple, things could be about to change for flirty half-siblings Justin and Rebecca after a birthday gift from her mother's "friend" David prompts Rebecca to take a paternity test. Hmmmwhat was that about a big reveal? - Damian Holbrook

Read more preview for ABC's Brothers & Sisters.

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