Sara Ramirez, Jessica Capshaw Sara Ramirez, Jessica Capshaw

Come on, get happy! After dealing with a tragic school shooting last week, the docs of Seattle Grace Mercy West lighten up tonight (9/8c, ABC), according to Grey's Anatomy executive producer Krista Vernoff. "It's very funny," she says of the story line that finds a new batch of interns trailing the residents. "It's very Season 1 Grey's, seeing the ineptitude of the baby doctors."

There are also laughs at the expense of Arizona (Jessica Capshaw), who, desperate to get Callie (Sara Ramirez) back, turns to somebody she typically can't stand: Callie's BFF, Mark Sloan (Eric Dane). "Mark is nothing if not loyal to Callie, and he doesn't make it easy for Arizona to gain his advice," explains Vernoff. "What Arizona is dealing with throughout the episode is that she doesn't think she has any flaws, and Mark has no problem naming them for her — it's hilarious!"

But will eating humble pie be enough to convince Callie to give Arizona another shot? "Callie is a hopeless romantic and she's trying not to be hopeless this time," says Vernoff. "I think it's safe to say that love will win out in the end, but it's going to take a lot more work for Arizona to get her back." Vernoff adds that Calzona fans shouldn't expect a reconciliation anytime soon because, she says, "tonight's episode is a cliff-hanger in terms of the state of their relationship." And the next new episode won't air until February 3 — news that might just wipe the smile right off your face.

Subscribe to TV Guide Magazine now!