In the sixth season premiere, Ross and Rachel's marriage is established to be a drunken mistake, and they divorce several episodes later. Monica and Chandler decide to move into her apartment together, and Rachel moves in with Phoebe. Joey lands a role on a cable television series called Mac and C.H.E.E.S.E, where he stars alongside a robot. Ross gets a job lecturing at New York University, and starts dating one of his students, Elizabeth (Alexandra Holden). Phoebe and Rachel's apartment catches fire, and Rachel moves in with Joey while Phoebe moves in with Chandler and Monica. Chandler decides to propose to Monica, who considers reconciling with Richard. Although Richard confesses that he still loves her, Monica accepts Chandler's proposal.

Season five features Monica and Chandler trying to keep their new relationship a secret from their friends. Phoebe gives birth to triplets in the show's one hundredth episode. She gives birth to a boy, Frank Jr. Jr., and two girls: Leslie, and Chandler. They decided to keep the name Chandler, despite thinking the baby was a boy. Ross and Emily's marriage is called off as Emily is intimidated by Rachel, and Ross refuses to stay away from her, as Emily demands. Phoebe starts a relationship with police officer Gary (Michael Rapaport). Monica and Chandler go public with their relationship, to the surprise of their friends. They decide to get married on a trip to Las Vegas, but change their plans after witnessing Ross and Rachel drunkenly stumble out of the wedding chapel.

In the fourth season premiere, Ross and Rachel reconcile but soon break up again. Phoebe becomes a surrogate mother for her brother and his wife Alice (Debra Jo Rupp). Monica and Rachel are forced to switch apartments with Joey and Chandler after losing a bet, but manage to switch back by bribing them with Knicks season tickets and a one-minute kiss between themselves. Ross begins dating an English woman named Emily (Helen Baxendale), and the season finale features their wedding in London. Chandler and Monica sleep together, and Rachel decides to attend Ross and Emily's wedding. While saying his vows, Ross uses the wrong name at the altar (Rachel's), to the shock of his bride and the guests.

Season three takes on a significantly greater serialized format.^[24] Rachel begins working at Bloomingdale's, an upscale department store chain, and Ross becomes jealous of her colleague, Mark. Ross and Rachel decide to take a break; however, Ross is confused by this arrangement and sleeps with someone else, causing Rachel to break up with him. After believing she has no family except her twin sister Ursula (Lisa Kudrow), Phoebe becomes acquainted with her half-brother (Giovani Ribisi) and birth mother (Teri Garr). Joey develops a relationship with his acting partner Kate (Dina Meyer), and Monica begins a relationship with millionaire Pete Becker (Jon Favreau).

The second season begins with Rachel discovering that Ross is dating Julie (Lauren Tom), someone he knew from grad school. Rachel's attempts to tell Ross she likes him mirror his failed attempts in the first season, although the characters eventually begin a relationship. Joey gets a part in a fictional version of the soap opera Days of our Lives, but his character is killed off after he claims that he writes many of his own lines. Monica begins dating Richard (Tom Selleck), recently divorced and 21 years her senior. In the season finale, they end their relationship when they realize that unlike Monica, Richard does not want children.

SYNOPSIS

The first season introduces the six main characters: Rachel, Monica, Phoebe, Joey, Chandler, and Ross. Rachel arrives at Central Perk after leaving her fiancé Barry at the altar and moves into Monica's apartment with her. Ross constantly tries to tell Rachel that he loves her, while his lesbian ex-wife, Carol, is expecting his baby. Joey is shown to be a struggling actor, while Phoebe works as a masseuse. Chandler breaks up with girlfriend Janice (Maggie Wheeler), who frequently returns in later seasons. At the end of the season, Chandler accidentally reveals that Ross loves Rachel, who realizes that she feels the same way.

Season Four

Season Four consists of 22 episodes that aired on Thursdays at 9:00 pm in the United States beginning September 18, 2008, and ending May 14, 2009.^[110]

Dean is rescued from hell and brought back by an angel named Castiel; one of several angels that appears throughout the season. The rest of the season follows the brothers as they work with the Castiel to stop Lilith's plan of breaking the 66 seals, which would allow Lucifer to walk free once again. Sam and Dean's relationship is also strained as Sam starts siding with Ruby over Dean. He also begins to give into his demonic side by drinking demon blood to become strong enough to defeat Lilith. After tracking down and killing Lilith, Sam learns that her death is actually the last seal and that Ruby was deceieving him all along. Dean arrives too late to stop him, but kills Ruby as Lucifer's prison opens up beneath them.

Season Three

Season Three consists of 16 episodes that aired on Thursdays at 9:00 pm in the United States beginning October 4, 2007, and ending May 15, 2008.^[108] Originally 22 episodes were ordered for the third season, but production was halted on December 5, 2007, upon completion of the twelfth episode due to the 2007–2008 Writers Guild of America strike. The season number was shortened to sixteen episodes, with four new episodes airing in April and May 2008.^[109]

The season mainly focuses on trying to save Dean from his deal and tracking down the demons that were released from the gate. Along the way, the brothers meet a demon named Ruby, who has an interest in Sam and claims to be able to help save Dean. Also, they meet Bela Talbot, an "acquirer" and seller of occult objects, who is constantly a thorn in their side. The brothers eventually learn what demon holds Dean's contract; a being of great power named [[Lilith (Supernatural)|Lilith. The brothers, along with Ruby, track her down and attempt to kill her. Lilith is unable to stop Sam due to his mysterious abilities, however, Dean's contract expires and his soul is taken to hell.

Season Two consists of 22 episodes that aired on Thursdays at 9:00 pm in the United States beginning September 28, 2006, and ending May 17, 2007.^[107]

The season follows Sam and Dean as they deal with their father's death and continue to hunt the yellow-eyed demon with assistance from new allies Ellen, Jo, and Ash. Part of the demon's master plan is eventually revealed as he gathers Sam and others like him, leading to Sam dying. Dean makes a deal with a crossroads demon to bring back Sam in exchange for his soul, which will be collected in one year. In a final confrontation, in which Dean kills the yellow-eyed demon, a hell's gate is opened, releasing numerous demons from within.

Season One consists of 22 episodes that aired in the United States beginning September 13, 2005, and ending May 4, 2006. The first sixteen episodes aired on Tuesdays at 9:00 pm, after which the series was rescheduled to Thursdays.^[106]

Two brothers, Sam and Dean Winchester, team up to find their father, John, who went missing on a hunting trip. However, their father isn't a typical hunter: he hunts supernatural creatures like ghosts, vampires, and various demons and he's trained his sons to do the same. Along the way, Sam and Dean save innocent people, fight creatures and ghosts, and collect clues to their father's whereabouts. Sam begins to mysteriously develop psychic abilities and visions as they travel. They eventually find their father, who reveals that the creature that killed Sam and Dean's mother years earlier is a yellow-eyed demon and the only thing that can kill him is a legendary gun created by Samuel Colt.

eason 2 featured 25 episodes and began airing on September 1, 2008 starting at the end of the summer instead of the more conventional start in the fall along with larger TV networks. The season concluded on May 25, 2009. The season premiered with 3.43 million viewers,^[9] similar to the first season and ended with 2.23, lower than expected.

The second season mainly explores the senior year of most of the characters, the continuity of their new found relationships, their final encounter with "Gossip Girl", and their attempts to get into college. The first couple of episodes feature part of the summer vacation, respectively week before the start of the school year. 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 second season also focuses on Blair and Chuck, who were labeled "the heart of GG" by People magazine.^[10] At first, both characters negate their feelings for one another, and go through random schemes and manipulations. After all the games are done, both of them eventually say "I love you" to each other. Other storylines include Blair's attempt to enter Yale University; the death of Bart Bass which proves to be a very bad influence on Chuck and the exploration of his involvements; Dan's transformation from outsider to insider and his relationship with Serena's teacher Rachel Carr; Serena's relationships after breaking up with Dan; Jenny's career as fashion designer and her rebellions which ultimately ends with her becoming the next Queen Bee; the end of Nate and Chuck's friendship and Nate's friendship with Dan; Nate's family problems which continue to grow and affect on his new found relationship with Vanessa; Rufus and Lily's relationship after Bart's death, their engagement, and revelation that they have a son; and Serena's involvement with Poppy Lifton, a secretive socialite that tries to steal money from Serena and her friends which ultimately leads to the return of Georgina Sparks, who claims to be changed but eventually decides to get revenge on Blair.

The penultimate episode of the season, "Valley Girls", was a backdoor pilot for a Gossip Girl spin-off series also titled Valley Girls. The series was set in 1983 and chronicled the teen years of the Gossip Girl character Lily van der Woodsen.