This week's episode of "Grey's Anatomy" season 12 shows Meredith's struggle to deal with the pain of the past, which continues to physically haunt her in the form of "perfect Penny," who is Callie's new girlfriend.

But as it turns out, the dinner party will only be their first encounter after Derek's death. In fact, Meredith will see the face of the "killer" of her husband at her workplace every single day. In the new installment titled "The Me Nobody Knows," Penny becomes the newest doctor on the team.

In the "Grey's Anatomy" season 12 episode, Grey Sloan Memorial Hospital welcomes Penny as the new resident doctor but she won't necessarily feel at home in her new office. The awkward shocks from new co-workers are just the start of a hellish stay there.

Needless to say, Meredith is not at all on board the idea of working with the person that basically killed her husband. In the promo for the episode, Penny tells her "I just want to say I don't want to today to be awkward." Narrowly allowing her to finish, Meredith replies, "So don't make it awkward."

Apart from the awkwardness and the yells, Penny will suffer Meredith's piercing stares. At one point, Meredith questions once again her credibility as a doctor and shouts to her, "Is there any part of this job that you can handle?" making Penny look like ashamed.

Meanwhile, Andrew and Maggie's hook-up had the latter thinking of ways to take it to the next level, but not until "an old friend" shows up out of the blue in the hospital. More than the already chaotic setting, the "Grey's Anatomy" season 12 episode will also bring in a couple of interesting patients.

April has to deal with a young boy from Middle East as the whole hospital talks about another one whose sex tape becomes the center of attention at the place.

"Grey's Anatomy" season 12 episode 6 "The Me Nobody Knows" airs Oct. 29 at 8 p.m. ET on ABC.