Series overviewMain article: List of Gossip Girl episodesSeason One: 2007–2008Main article: Gossip Girl (season 1)The first season's main focus is Serena's sudden return to the Upper East Side following her mysterious disappearance. Initially, Serena's one night-stand with Nate Archibald, lover to Serena's best friend Blair Waldorf, was thought to be Serena's reason to leave. However, near the end of the season, the cunning Georgina Sparks, Serena's former friend, arrives on the Upper East Side, revealing that the night Serena slept with Nate didn't end there – Serena went to meet Georgina at the Stanhope Hotel and a man died in her presence under the influence of drugs, while being taped. The season also revolves around Serena's relationship with outsider Dan Humphrey; Blair's relationship with Nate and her affair with his best friend Chuck; brief romance between Serena's mother and Dan's father; Blair and Jenny's mentor-protege relationship; and the arrival of Dan's former best friend Vanessa Abrams. The season ends with the revelation of Serena's secret, causing the break up of Dan and Serena, and Chuck leaving Blair at the airport while she finds a new fun summer fling, before leaving for Europe.Season Two: 2008–2009Main article: Gossip Girl (season 2)The second season mainly explores the senior year of the characters with the premiere at the Hamptons and primarily focused on the relationship between Blair and Chuck, who were labeled "the heart of GG" by People magazine. At first, both characters negate their feelings for one another, and go through random schemes and manipulations.The first half of the season deals with Serena's growing prominence as a socialite which draws the attention of Blair as their friendship is tested when the character of Poppy Lifton (Tamara Feldman) arrives, a socialite who inadvertently drives a wedge between Serena and Blair after inspiring Serena to take her place in the spotlight during the early episodes of the season. Nate faces the aftermath of his father's criminal past and pursues a relationship with Vanessa, who becomes further entangled into the world of the Upper East Side. Jenny reignites her rebellious nature by pursuing a career as a fashion designer, thereby challenging Rufus' skills as a parent while Dan's friendship with Nate and relationship with Serena slowly transforms him from a social outcast to an insider. The show finished its first half during the first week of December, with the shocking death of Bart Bass.The second half of the season reveals the impact of Bart's death, causing a significant change of character direction for Chuck that subsequently leads to the growth of Rufus and Lily's relationship, the revelation of the two having a son together, and contributing to the decline of Dan and Serena's relationship. John Shea reprised his role as Harold Waldorf during a Thanksgiving episode and becomes entangled in Blair's striving ambition of attending Yale. Desmond Harrington entered the series as Chuck's manipulative uncle, Jack Bass. Feldman returned to the season with Armie Hammer as Serena's new love interest, Gabriel Edwards. Michelle Trachtenburg returned to the role of Georgina Sparks and filmed her scenes during February, also adjoining her character's return to the second season mystery.A backdoor pilot for a spin-off premiered in May but was not picked up by The CW to the limited number of spots available on their fall line-up.As the storylines progressed, the role of "Gossip Girl" is slightly decreased. She continues to run her blog, but she keeps the ultimate information for herself, sending it in the final episode as the last blast, where Serena decides to find out who "Gossip Girl" really is, but ultimately fails. The season finale ended with a well-received kiss between Blair and Chuck.Season Three: 2009–2010Main article: Gossip Girl (season 3)The third season focuses on Blair, Dan & Vanessa getting into NYU along with movie star Olivia Burke (Hilary Duff), whom Dan starts dating; Nate getting into Columbia University; Serena taking a year off from school; Jenny becoming Queen Bee at Constance; and Chuck running Bass Industries, along with now adoptive mother Lily van der Woodsen. The first couple of episodes feature part of the summer vacation, respectively the week before the start of University and School. The role of "Gossip Girl" is slightly decreased throughout the season.Many guest stars were cast throughout the season including Joanna García as Bree Buckley, a love interest for Nate; America's Next Top Model creator Tyra Banks as Ursula Nyquist, a larger than life actress whom Serena served as a publicist for a short time; William Baldwin as William van der Woodsen, Serena and Eric’s father, Lily’s ex-husband and Rufus’ long-time rival; and cameos by Lady Gaga, Tory Burch, Jimmy Fallon, Plastiscines, Georgina Chapman and Sonic Youth.The ninth episode of the season caused a significant amount of controversy. Parent groups urged the CW not to air the episode that contained a threesome. The preview for the episode revolved around an "OM3" theme. CW ignored these requests and announced that it was going to air the episode as planned.Robert John Burke, who played Chuck's father, Bart Bass, returned for A Christmas Carol themed episode in December, while Desmond Harrington returned as Chuck's uncle Jack with a major storyline affecting Chuck and Blair's relationship again and involving Chuck's estranged mother Evelyn Bass Fisher (Laura Harring).The season focused hugely on Jenny Humphrey's development and downward spiral. She spends a good part of the season alienating herself from Eric, her former best friend, and chasing after Nate, who has his heart set on Serena. At the end of the season, due to her one night stand with Chuck Bass, and new drug dealing habit, Jenny's father and Lily send her to Hudson, New York, to live with her mother. Other story lines include: Blair and Chuck's attempt and ultimate failure at having a successful relationship; Dan and Vanessa moving from friends to something more; and Serena's attempts to find herself through a new job and brief love affairs with Carter, Nate's married cousin Tripp, and eventually Nate himself.Season Four: 2010–2011Main article: Gossip Girl (season 4)Season four's main mystery revolves around Juliet Sharp (Katie Cassidy), a secretive girl with an agenda against Serena involving her past. The second half of the season builds on the complications of Serena's new found relationship with her former teacher Ben, Chuck trying to regain control of Bass Industries from Russell Thorpe (Michael Boatman), and Dan and Blair's growing friendship. The season also focuses on Lily's past betrayals coming back to haunt her; Chuck and Blair's tumultuous relationship after their break up; Dan and Vanessa's deteriorating friendship; and the arrival of Serena's cousin Charlie Rhodes (Kaylee DeFer) to the Upper East Side.The first two episodes of the season took place with Serena, Blair, and Chuck in Paris. While in Paris, Blair meets Prince Louis Grimaldi, to whom she later becomes engaged at the end of the season.Taylor Momsen, who plays Jenny Humphrey, was absent for the majority of the season but made appearances in "Easy J", "Juliet Doesn't Live Here Anymore", "The Witches of Bushwick", and "Gaslit".Season Five: 2011–2012Main article: Gossip Girl (season 5)The series was renewed by The CW for a fifth season on April 26, 2011.On May 9, 2011, it was announced that Taylor Momsen and Jessica Szohr would not be back as series regulars, although both have been invited back as guest stars. Kaylee DeFer plays a character named Ivy Dickens who is being paid by Lily's sister, Carol Rhodes (Sheila Kelley), to impersonate her daughter, Serena's cousin Charlie Rhodes (Ella Rae Peck). She was also promoted to series regular status for season 5.The season began in Los Angeles when a re-energized Chuck and Nate decided to pay Serena a visit. Chuck has a new found philosophy and says "yes" to everything, even death defying stunts. Serena continues to work on the movie set, and is offered a full-time job at the end of the episode. Nate begins an affair with an older woman, Diana Payne, who may have an ulterior motive for being with Nate. Back in New York, Dan learns that Vanessa has published one chapter of his novel, and Blair continues to plan her wedding to Louis, and she also learns she is pregnant. After realizing she still had feelings for Chuck, Blair and Chuck decide to go away together, but their car gets crashed. As a result of the crash Blair loses her baby, Chuck nearly dies and she eventually marries Louis. The season also focuses on Nate running newspaper The Spectator, on the friendship turning into a relationship between Blair and Dan, on Chuck's quest to find his real parents which leads him to discover that his father, Bart, is still alive, and on the effects CeCe's death has on Lily and her marriage to Rufus. At the end of the season, Blair makes a choice between Dan and Chuck and so does Lily between Rufus and Bart. Serena is seen leaving town while Dan decides to write a new book about the Upper East Side, with the help of Georgina.Season Six: 2012On May 11, 2012, it was announced Gossip Girl would return for a shortened sixth and final season beginning in fall 2012. During the CW upfronts, the network president Mark Pedowitz said the amount of episodes hasn't yet been decided and might consist of 10, 11, or 13 episodes with a retrospective. The show is expected to end before Christmas.BroadcastGossip Girl airs on The CW, Mondays at 8/7 central. The series is also broadcasted in 197 countries.