Complete Series DVDS

The show was renewed for a fourth season, with the first episode airing on September 27, 2007. In the official blog, creator Shonda Rhimes gave a few clues as to plotlines for season four, indicating that Mark Sloan will be given a bigger role and in the aftermath of the finale, events for Derek Shepherd and Cristina Yang will be "interesting to watch."[11] Due to her producing responsibilities on both Grey’s and the spin-off, Rhimes assigned the day-to-day showrunning duties to writer and executive producer Krista Vernoff.[12] For the first time in the show's history, many of the series regulars were not returning. Kate Walsh's character was transferred to the Grey’s Anatomy spin-off, Private Practice. On June 7, 2007, it was announced that Isaiah Washington's contract had not been renewed.[13] Former Reunion star, Chyler Leigh, guest starred in the final two episodes of season three as Lexie Grey, a new intern and Meredith Grey’s younger half-sister. On June 11, 2007, it was announced that Leigh would become a series regular, instead of a 13 episode story arc as previously planned.[14] The character Dr. Erica Hahn (The Silence of the Lambs fame actress Brooke Smith) joined the main cast, reprising her antagonizing role in the season's fifth episode. She replaces Preston Burke as head of Cardiothoracics. Upon her return, she makes Sandra Oh's character, Cristina Yang work harder for her success in Cardiothoracics. It was reported that a new male character would be introduced. This character would somehow be in "competition" with Dr. Derek Shepherd.[15] Fourth season guest stars included former Gilmore Girls actor Edward Herrmann who appeared in three episodes. Seth Green of Buffy the Vampire Slayer fame guest starred in a two-part episode.[16] Lauren Stamile plays a scrub nurse named Rose, who became a potential love interest for Derek.[17] Dawson's Creek alumnus Joshua Jackson was scheduled to make his return to television in a multi-episode arc as a doctor with his first appearance in the season's eleventh episode.[18] Jackson's appearance was cancelled due to the 2007–2008 Writers Guild of America strike.[19] Kate Walsh returned as Dr. Addison Montgomery on May 1. On February 20, 2008, it was confirmed that Grey’s Anatomy would return on April 24, 2008 for five new episodes.[20] Where the Wild Things Are was the first episode shown after the incubation resulted from WGA strike. The double episode finale (Freedom) aired May 22, 2008. It was centered around Meredith having a huge breakthrough with her personal life including Derek and her mother. Derek also realized he continually failed Meredith. Meredith and Derek performed clinical trials on patients with brain tumors. They lost all of their patients except for one whose boyfriend died just before her life saving surgery. After finally succeeding, Meredith finally took a risk and reunited with Derek. Almost all the cast had a kiss, including Meredith and Derek, George and Lexie, Richard and Adele, Alex and Izzie, and, Erica and Callie. To prepare for the lesbian story line, which will continue in season five, Grey’s consulted with GLAAD.[21] We also learned about Alex's needy mother and part of his past. After Meredith and Derek's resumption of their relationship, Derek left to break up with Rose, his girlfriend who had come between the two previously.

Episode	Description
#1	A Change Is Gonna Come Having just returned from her honeymoon with Meredith, Cristina searches for Burke, but he's nowhere to be found. Meredith, Cristina, Izzie and Alex spend their first day as residents with their own groups of interns - among the interns are George, repeating his intern year after failing his exams, and Lexie Grey, Meredith's half-sister whom she has never met. Now that Derek's relationship with Meredith has reached an emotional impasse, he looks to his fellow doctors for friendship; Bailey wrestles with her place within the hospital now that her former interns report to new Chief Resident Callie; and Richard resumes his position as Chief of Surgery.
#2	Love/Addiction The residents and interns treat the victims of a massive explosion at an apartment building, while Alex investigates the cause of the accident, Mama Burke returns to collect her son's things just as Cristina trades her wedding presents in exchange for surgeries, Lexie tries to have a heart-to-heart with an unwilling Meredith, and while Callie is overwhelmed with her duties as Chief Resident, Bailey searches for an outlet for her pent-up leadership skills.
#3	Let the Truth Sting Meredith reluctantly helps Lexie with her first surgical procedure, while Lexie helps keep George's 'repeater' status a secret from their fellow interns.
#4	The Heart of the Matter Izzie confides in Alex about George and the reaction is not what she expected, the Chief's niece returns to the hospital where she once had her prom, and Derek teaches Cristina how to be a better resident to her interns.
#5	Haunt You Every Day Halloween is full of surprises for the Seattle Grace doctors when Ava makes an unexpected visit to see Alex, Meredith thinks her deceased mother is haunting her, and Callie reveals George and Izzie's affair to their fellow doctors.
#6	Kung Fu Fighting With his marriage in trouble, the Chief turns to his fellow male surgeons for a 'gentlemen's evening,' Cristina and Izzie heatedly compete for the same surgery, and the doctors treat two injured finalists from a promotional wedding competition.
#7	Physical Attraction, Chemical Reaction George and Izzie's romantic chemistry is put to the test, Mark develops a crush on a fellow surgeon, and Callie's role as Chief Resident is in jeopardy.
#8	Forever Young A schoolbus crash floods Seattle Grace with teenagers, Derek goes out on a date with a fellow doctor, and Meredith sees her father for the first time since her stepmother's death.
#9	Crash Into Me, Part 1 Part one of a two-part episode. An ambulance crash endangers the lives of the paramedics involved, as Meredith and the Chief work on-site to save them, Bailey treats a patient who refuses her help, and Ava returns for Alex and meets his other girlfriend in the process.
#10	Crash Into Me, Part 2 Part two of a two-part episode. Meredith furiously works to save the life of a paramedic trapped inside an ambulance, as her sister, Lexie, holds the life of a patient in her hands, and Derek must rely on the help of a nurse to save a patient's life.
#11	Lay Your Hands On Me Bailey's family faces a medical trauma just as her marriage is falling apart, George receives a very unexpected visit from his mother, and a faith healer wishes to forgo traditional surgery.
#12	Where the Wild Things Are Six weeks have passed since Derek started dating Rose, and the new residents are competing in a surgical contest. George and Lexie move into their new apartment while Callie and Erica continue their friendship.
#13	Piece of My Heart Addison returns to Seattle Grace to perform an operation and is surprised by all the changes in the lives of her former co-workers; Derek and Meredith's clinical trial has its first patient; Rebecca returns with shocking news for Alex.
#14	The Becoming A date and tell policy is instated at Seattle Grace after the nurses object to Mark's trysts, Cristina has to face her feelings for Burke and Meredith and Derek admit a veteran soldier into their clinical trial.
#15	Losing My Mind Dr. Wyatt refuses to let Meredith give up on therapy, Alex learns the truth about Rebecca's medical condition, the Chief insists that Erica perform a risky surgery on his mentor, and after receiving news of Burke, Cristina continues to do things contrary to her nature, going so far as cleaning her always-messy apartment.
#16	Freedom, Part 1 Part one of a two-hour season finale. Meredith and Derek work on their last patient in their clinical trial, as the other surgeons try desperately to free a boy from a hardening block of cement. Izzie helps Alex care for Rebecca, and Lexie discovers important information about George's intern status. Callie confronts her feelings about Erica.
#17	Freedom, Part 2 Part two of a two-hour season finale. Meredith and Derek work on their last patient in their clinical trial, as the other surgeons try desperately to free a boy from a hardening block of cement. Izzie helps Alex care for Rebecca, and Lexie discovers important information about George's intern status. Callie confronts her feelings about Erica.