Grey's Anatomy

Meredith is faced with a tough decision that will affect the life of a loved one, Callie is rocked by the reality of Arizona's infidelity, and Richard's life is in extreme danger.

The fight continues to save those affected by the storm, Callie makes a bold decision regarding her relationship, and the doctors come together upon receiving devastating news.

Meredith and Derek adjust to life at home with a newborn; Arizona tries to fix her marriage; Alex and Jo navigate their relationship; Owen clashes with Jackson over financial issues, and April awaits her boards results.

The doctors throw a fundraising gala which turns competitive after Jackson makes a rash promise. Bailey's patience is tested when she has to deal with difficult patients. Shane and Stephanie handle a busy ER by themselves.

Meredith finds it hard to excel at both motherhood and being a surgeon. Jo finds herself overly involved with her new patient. Callie and Owen deal with an emotional situation regarding a patient.

Derek and Callie work on a brain mapping project, Richard encourages the interns to use his condition as a learning tool and after a discussion with Callie, Meredith considers continuing her mother's research.

It's Halloween and the doctors are hit with a barrage of spooky patients, which affects their own plans and puts one doctor's well-being in jeopardy. Derek collaborates with Ben on a surgical technique.

Issues between Meredith and Cristina hit a boiling point. Derek tells Jackson that he needs to let go and allow the second year doctors to work on his patients, Bailey has difficulties with Ben's return.

When a malpractice suit turns Callie's world upside down, her father arrives and shares a secret with her. Through flashbacks, we learn some surprising details about Callie and Arizona's marriage.

Ben worries that a casual conversation with Derek could potentially cause issues for Bailey and April's upcoming wedding makes for an uncomfortable situation between Jackson and Stephanie.

April's sisters arrive to help celebrate April's upcoming nuptials. Matthew and Jackson are forced to work together, Callie and Arizona work hard to reestablish their relationship.

On the day of April's wedding, the doctors are all preoccupied with their own drama. Meredith and Cristina continue to argue about their research and careers and Bailey comes clean to Ben about her feelings.

The doctors face the consequences of the events that took place at April's wedding. Meredith feels betrayed when Derek goes back on a promise, and Arizona and Callie decide whether or not to move forward together.

After a complaint, the hospital implements a non-fraternizing policy causing the couples to panic. Emma and Owen talk about the future, Cristina and Meredith enjoy girl time and Richard enlists the residents to help research.

Arizona advises one of Callie's patients on a potential double amputation. The doctors deal with the repercussions of the non-fraternization rule, which include meetings with HR and one doctor's suspension.

It's Richard's birthday and Bailey invites him to scrub in on the case of a lifetime. Meredith hires a research assistant to help with her portal vein project, and a scorned Callie gives Derek quite the shock.

Cristina imagines the two routes her life can take based on one decision she makes. Meanwhile one of the hospital's patients decides whether or not to live.

The hospital gets inundated with flu infected patients, which causes the doctors to slowly fall ill one by one. Derek prepares to give a speech on brain mapping.

Cristina is nominated for a Harper Avery and won't let herself get too excited. Bailey continues to work on a boy without an immune system. Richard gives the residents a pep talk.

Cristina enlists Meredith to help her prepare a speech for her possible Harper Avery win and while Owen offers to attend the ceremony with her, she insists on going alone.

Jackson is given the task of delivering disappointing news to the doctors. Derek's sister Amelia drops by for a visit, Richard surprises Catherine in Boston and Bailey gets frustrated by the slow pace of her research.

Cristina looks to Meredith for advice as she assesses her future at the hospital. Derek and Amelia work together on a difficult surgery involving conjoined twins.

Meredith spends time with Amelia and finds out her true feelings about her time in Seattle. Bailey deals with the ramifications of her actions and Callie receives devastating news.

The doctors bid farewell to Dr. Cristina Yang.