Meredith (Ellen Pompeo) will have to come clean about her affair with Nathan (Martin Henderson) if she wants to keep her good standing with her sister in the upcoming season of "Grey's Anatomy."

According to recent updates, the Seattle Grace will learn about the secret hookup between Meredith and Nathan during the second episode of the new installment. Kelly McCreary, who plays Maggie in the show, told TV Guide that her character would feel very bad to know that her sister did not tell her that she has been going out with her crush. Maggie told Meredith during the "Owelia" wedding that she really likes Nathan. That time, Meredith chose to remain silent, thinking Maggie would be hurt if she told the truth.

McCreary said that this would haunt Meredith, especially when the truth is revealed in episode 2. She said that for Maggie, trust is very important. Just like what she underwent when she learned that Richard (James Pickens Jr.) was actually her father, she would feel betrayed by Meredith. For Maggie, people who love each other do not keep secrets. It is also likely that her emotions will be dictated by her jealousy. After all, she has had a huge crush on Nathan for quite a while now. Will her sister have to end things with Nathan to make things all right?

"One of the things that we know about Maggie is that she is really a stickler for honesty and the truth. ... To me, that's an indication of how we can expect Maggie to feel about any lack of honesty, any lack of full transparency and disclosure in a relationship - especially with somebody that she trusts and, more than trusts, really relies upon as much as Meredith," the actress said.

Meanwhile, it has been currently teased that the new season will shift its focus on the original members of the show. Zap2it compiles a list of old characters that can make a comeback in the next installment. The first in line are Sandra Oh's Christina Yang and Katherine Heigl's Izzie Stevens. Christina's ex, Owen (Kevin McKidd), recently got married and it would be interesting if his ex-wife will suddenly arrive in Seattle Grace. The return of Alex's (Justin Chambers) ex just when he is having a difficult time with current girlfriend Jo (Camilla Luddington) will also make an explosive storyline.

"Grey's Anatomy" will return to ABC on Thursday, Sept. 22, at 8 p.m. EDT.