Fans finally discovered why beloved character Cristina Yang will be leaving Grey Sloan on the latest episode of "Grey's Anatomy."

In "We Are Never Ever Getting Back Together," Dr. Russell, the head of cardiology, leaves the hospital because Grey Sloan will never win a Harper Avery Award. The board then implores Cristina (Sandra Oh) to appeal the loss so they can set a precedent.

She avoids it by flying to Zurich to talk about 3D printing portal veins at a hospital where her ex, Burke (Isaiah Washington), now works. She discovers that he is the one who invited her to speak.

Burke gives Cristina a tour of the hospital, which is very high tech and has 49 3D printers. Burke wants Cristina to work at the hospital, but does not intend to reignite their relationship, as he's now married with two children.

She is unsure about working with him, but he tells her that she would be replacing him because he's leaving to spend more time with his family. He is practically handing her an entire hospital, meaning Cristina's most likely leaving Grey Sloan to move to Zurich.

Back at Grey, Sloan, Amelia (Caterina Scorsone) and Derek (Patrick Dempsey) perform a surgery, but Amelia is angry over being treated like his little sister. But when the surgery takes a turn for the worst, Amelia is able to save the day, and Derek proves that he respects her. He then invites her to work at the hospital full-time.

April (Sarah Drew) and Jackson (Jesse Williams) also get their baby's ultrasound, and decide to keep it, despite their continuing tension.

Jo (Camilla Luddington) also gets very overwhelmed at work, and Owen (Kevin McKidd) decides that he's going to fire one of the residents.

On the next episode, "Everything I Try to Do, Nothing Seems to Turn Out Right," "With Derek away, Meredith spends time with Amelia and finds out her true feelings about her time in Seattle. Bailey (Chandra Wilson) deals with the ramifications of her actions, and Callie (Sara Ramirez) receives devastating news. Meanwhile, the residents panic after hearing that one of them will be fired."

Watch the promo for the next episode below, which airs Thursday at 9 p.m. EST on ABC.