Season 1 "A Hard Day's Night"
Meredith shows up to her first day as a surgical intern only to find out that the guy she just slept with is her boss, Dr. Shepherd. In the meantime, the rest of the new interns are introduced to the backbreaking work they have cut out for them at Seattle Grace.
Season 2 "Raindrops Keep Falling on My Head"
In this eventful season premiere, the doctors must first deal with taking care of Joe the bartender who can't afford the surgery he needs. Meredith is dealing with the awkwardness of working on Addison's service, while Cristina reveals her pregnancy to Meredith but keeps it from Burke.
Season 3 "Time Has Come Today"
Izzie must learn to cope with the loss of Denny, while making the decision to quit the internship program. Addison realizes that her marriage with Derek is crumbling after learning he's still sleeping with Meredith. Dr. Webber and Adele are also having marriage issues, after Adele is seen giving him an ultimatum between his job and their marriage. Meanwhile, the doctors must treat a newborn baby who was found abandoned in a trash can.
Season 4 "A Change Is Gonna Come"
Meredith, Cristina, Izzie and Alex finally become residents with their own groups of interns, while George is left to repeat his intern year after failing his exams. We are introduced to Lexie Grey, Meredith's half-sister whom she has no idea exists. The doctors are faced with treating patients of a multi-car pile-up, while Dr. Webber resumes his position as Chief of Surgery.
Season 5 "Dream a Little Dream of Me"
This two-part season premiere introduces Owen Hunt to the hospital, where he first meets Cristina as her patient. Meanwhile, the ER is filled with car crash victims due to a snow storm, and the doctors are stressing out over the hospital's national ranking number dropping. The tables turn when Owen must treat Cristina's icicle wound, sparking a flame between the two. Lexie is battling the side effects of catching feelings for George, while Callie and Erica deal with the awkwardness of their kiss.
Season 6 "Good Mourning"
Although Izzie is shown to have survived her surgery, she is given the news that George has died. The rest of the staff must deal with the pain of losing George, each coping with the loss in their own way.
Season 7 "With You I'm Born Again"
In this premiere, the doctors are assessed and treated by a trauma counselor after recovering from the hospital shooting. Meredith is not cleared for surgery right away following the incident. Meanwhile, Cristina and Owen finally plan their wedding.
Season 8 "Free Falling"
When a giant sinkhole opens up in the middle of Seattle, April must step up as Chief Resident. Meredith must deal with the professional ramifications of tampering with Derek's medical trial, while Owen and Cristina are still discussing what to do about their unplanned pregnancy.
Season 9 "Going, Going, Gone"
A month following the plane crash, it's finally time for the doctors to take Mark off of life support. Cristina has moved to Minnesota and Alex worries that the new pediatric surgeon will destroy Arizona's program. However, at the end of the episode it's revealed that Arizona did survive the plane crash but had to have her leg amputated by Callie.
Season 10 "Seal Our Fate"
The ER becomes overrun following a bad storm. Heather finds Dr. Webber is unconscious in the basement after being electrocuted, in which she is then electrocuted herself. Meredith has given birth to her son, and Arizona desperately tries to mend her relationship with Callie after cheating on her. However, Arizona discovers that Callie has moved out and taken Sofia with her.
Season 11 "I Must Have Lost it on the Wind"
After Cristina leaves the series, Maggie Pierce must step us as the new cardiothoracic surgeon. Arizona's career advances when she accepts a position a fetal surgery fellow given to her by Dr. Herman. Meanwhile, Derek tells Meredith that he chooses her and the kids over his brain mapping initiative in Washington, D.C.
Season 12 "Sledgehammer"
At the hospital, two fifteen-year old old girls who were hit by a train admit their love for one another. Callie steps in to defend the girls to one of their mothers, while their fathers bond and learn to accept their daughters for who they are. Meanwhile, Bailey fights for the position as Chief of Surgery, and eventually gets it.
Season 13 "Undo"
During Amelia and Owen's wedding, Andrew is brought to the ER after being assaulted by Alex. Meredith faces the dilemma of whether to protect Alex or tell Bailey the truth about his actions. In the end, Meredith ends up revealing the truth about Alex to Bailey, but not after he's already turned himself into the police.
Season 14 "Break Down the House"
When Megan, Owen's sister who is revealed to actually be alive after a ten year absence reappears, Meredith finds herself in a love triangle between Megan and Nathan. Teddy Altman also comes back to Seattle to support Owen and his mom, causing awkward interactions with Amelia. Meanwhile, DeLuca comes home to find his sister half-naked on the couch with Arizona.
Season 15 "With a Wonder and a Wild Desire"
Meredith struggles to focus on her work while being distracted by her sex dreams. Teddy reveals to Maggie that she's pregnant with Owen's baby, which makes things complicated because Owen and Amelia are now living together. We are also introduced to new characters Atticus “Link” Lincoln and Nico Kim.