A surprise visitor from the past is planning to pop up in Season 13 of “Grey’s Anatomy” and shake things up for members of the cast.

According to a synopsis for episode 6 — titled “Roar” — the visitor will resurface old feelings, “throwing many of the doctors for a loop.” There is no indication who the visitor may be, but that hasn’t stopped “Grey’s Anatomy” fans from speculating. Some have questioned whether Izzie (Katherine Heigl) or Cristina Yang (Sandra Oh) may be making their way back to the set. While that would certainly bring about interesting feelings for Meredith (Ellen Pompeo) and Alex (Justin Chambers), photos from the episode confirm that the returning cast member is Tessa Ferrer, who played Leah Murphy.

Speaking of Alex, his decision to violently attack DeLuca (Giacomo Gianniotti) in the Season 12 finale will rear its ugly head once more. Catherine (Debbie Allen) will pressure Bailey (Chandra Wilson) to make a decision about Alex’s fate at Grey-Sloan Memorial. He is currently stuck working shifts in the clinic, which he hates more than anything. It is not clear which way Bailey is leaning, but we’re crossing our fingers that despite the attack, he’ll be able to keep his job.

While Bailey wrestles with a tough management decision, Amelia is coping with a bad day. A tough case in the emergency room will further complicate her feelings, making things worse. Could her struggles be related to having learned that she’s not pregnant after all?

Photos for the episode tease major drama to come in Season 13, episode 6.