When the Chief makes an announcement that a solo surgery is up as an award, the residents are sent into a frenzy all trying to get an edge over one another. Meanwhile, Derek asks Bailey for advice after Cristina continues to interfere in his relationship with Meredith. Elsewhere, Erica uncovers a shocking connection between a resident and a patient.

Now that Derek has the engagement ring, he searches for the perfect way to propose to Meredith, as Lexie demands that Mark go public with their relationship, and Bailey, encouraged by her work on recent cases and by Dr. Dixon, considers a new direction for her medical career.

After a burn victim unexpectedly dies in the midst of a chaotic ER, the Chief and board member Jennings interrogate the residents to find the culprit, as all the Mercy West and Seattle Grace resident defends their actions in an effort to save their jobs.

It's Valentine's Day, and the doctors must treat dozens of injured people after the roof collapses at a popular romantic restaurant; Derek tries to manage his busy schedule as Chief of Surgery; Meredith wrestles with her new duties as the Chief's wife; and Mark and Callie team up to convince Sloan to do the right thing for her baby.

Meredith finally tells Derek about her pregnancy and miscarriage; during a surgery, Cristina experiences PTSD; Bailey won't let Alex operate until he has the bullet in his chest removed.

A team of doctors tries to save the life of a political figure from the Middle East; Cristina decides to decorate her new place and throw a housewarming party; Alex shows up late to his first day of rounds with the new pediatrics attending.

Everyone pulls together to help Callie and baby Sofia on their painstaking journeys to recovery in hopes of allowing mother and baby to finally meet; the sudden death of a clinical trial patient has Derek proceeding with more caution while Meredith makes a calculated and risky move; Alex treats a cranky old rich woman dying of cancer and gets an idea for a grandiose endeavor that is sure to get him the Chief Resident spot; and Teddy is pleasantly surprised by the return of a familiar face.

The chief makes a decision that shocks everyone at Seattle Grace; Owen and Cristina attempt to find normalcy; April struggles in her new role; the 5th-year residents receive their first solo surgery assignments.

As Meredith puts Zola to bed and falls asleep, she begins to wonder -- what if her mother had never had Alzheimer's and she'd had loving, supportive parents? The reverberations of a happy Meredith Grey change the world of Seattle Grace as we know it. What if she had never met Derek in that bar and he had never separated from Addison? What if Callie and Owen had become a couple long before she met Arizona? And what if Bailey never evolved from the meek intern she once was?

Derek encourages a hesitant Meredith to work with him again in neurology; Jackson's mother, Catherine Avery, returns to Seattle Grace with a urology fellow and develops an interest in Richard; and Cristina becomes increasingly suspicious of Owen's every move. Meanwhile, Alex tries to deny the fact that Morgan may be falling for him.

In this flashback episode, return to the site of the plane crash and watch as each doctor tries to cope with the heartache and injuries caused by the crash. Meanwhile, back at Seattle Grace, everyone struggles to find a bit of normalcy amidst the chaos.

As the hospital spirals closer to financial ruin, Owen must make some tough decisions, which includes foregoing an expensive surgery that could save the life of a child. Meanwhile, Alex and Jo work together to save the life of an infant, and April asks Jackson for dating advice.

Maggie and Meredith disagree with Derek about the best way to approach a patient’s case, which leads to a bigger argument between the couple. Meanwhile Callie feels responsible when one of her veterans is pushed too far and one doctor’s routine procedure results in a devastating diagnosis.

As the doctors continue to tackle an unfathomable crisis, they are reminded of what is important and are brought closer together.

Maggie reevaluates her life choices after receiving an invitation to her ex-boyfriend’s wedding; Richard questions Bailey’s loyalty, and Jo confides in Stephanie about a secret she’s been keeping from Alex. Meanwhile, Alex struggles with making a difficult decision that will affect the lives of newborn twins.

A patient from Meredith's very first surgery as an Intern is readmitted to Grey Sloan Memorial with a new aneurysm, and Amelia takes her case. Meanwhile, Maggie suspects that Richard knows about her relationship with Andrew, and Arizona debates dating again.

Meredith and Maggie support Amelia on an important day; Jo reveals that she has been keeping secrets from Alex while Arizona and Callie deal with the impact of their custody arrangement. Meanwhile, Ben leaps into action to help a friend.

When one of Grey Sloan’s own lands in the hospital, Bailey tries to figure out what happened while the rest of the doctors jump in to help. Meredith juggles huge secrets that affect her relationships with Alex and Maggie. While Richard helps Jo with a big decision, April and Catherine clash over the new baby.

The doctors of Grey Sloan encounter a difficult case involving a dangerous patient. Meanwhile, Owen receives life-changing news that pushes Amelia to step up to support him, and Alex attends a medical conference after making a shocking discovery.

A hacker compromises the hospital’s computer system, causing monitors, phones, labs and patient files to all go down. As technology fails them, Bailey attempts to keep the peace but chaos erupts and the doctors are forced to get creative in their methods to treat the patients.

One of Grey Sloan Memorial’s own is seriously injured, making the team reflect on what is truly important to them. Meanwhile, Nicole Herman pays a visit to Grey Sloan and talks to Arizona about an exciting opportunity.

Meredith turns heads when she shows up to work done up and ready for her blind date later that day, while Alex makes a questionable decision in order to save a patient. Meanwhile, the burden of knowing Teddy’s secret keeps Maggie up at night, ultimately making her decide she has to tell someone.

Ties are strained as Andrew and Carina confront an unforgiving family history. Meanwhile, Teddy and Owen work together on a married couple who is expecting, and Amelia attends a conference for alternative pain relief.