The eighth and final season of the American comedy television series That '70s Show premiered November 2, 2005 on Fox in the United States. The season ended on May 18, 2006 with an hour-long series finale. The eighth season was the first and only season without the show's star Topher Grace who portrayed Eric Forman, the central character, since he left the series at the end of the previous season. This season also marked a major change in the series, as a new character was introduced to take Eric's place named Randy Pearson and the departure of Michael Kelso, who was portrayed by Ashton Kutcher. Kutcher actually quit the show at the end of season seven but remained on the series for five episodes during the eighth season. He appeared in the first four episodes to give closure to Kelso and he appeared again in the final episode titled "That '70s Finale". Topher Grace also returned for the final episode but his role was both brief and uncredited. Also, Leo returned as a main character since his return to the series in the seventh season.
Many plots of the season involved Donna's new relationship with Randy, Jackie falling in love with Fez, Hyde getting married to a stripper named Samantha, Kelso getting a new job and moving to Chicago, and the Formans adjusting to an empty nest which is too empty for Kitty and not empty enough for Red due to the kids' presence despite Eric's absence.
The eighth season picks up with Kitty and Red discovering their empty nest isn't very empty, even with Eric in Africa. Meanwhile, Hyde returns from Las Vegas, where he went to clear his mind after catching Jackie and Kelso in a compromising position. But when Kelso and Donna tell Jackie that Hyde planned on proposing to her, Jackie tries to win him back, only to discover that what happens in Vegas, doesn't necessarily stay in Vegas.
Things go from bad to worse for Hyde, who discovers that while he was away, Leo nearly put the record store out of business. But Hyde's plan to fire Leo goes up in smoke when he ends up keeping Leo and hiring a new guy, Randy. Meanwhile, in an effort to get over Hyde, Jackie drags Donna and Fez out for a night on the town, but ends up humiliated when she reveals a little too much.
Even though Hyde insists that he doesn't want a bachelor party, the guys throw one for him anyway. Randy puts Fez in charge of creating a way to get Hyde to the party without him knowing what's going on; Fez's plan depends on Kelso, who gets side-tracked by the new girl at the ice cream store. Meanwhile, Jackie wants to have a girls' night with Donna and is shocked to find out that Donna has become friends with Sam.
Red and Kitty are celebrating their 25th Wedding Anniversary, and this makes Kelso think that it's time for him to get married. He decides to propose, but before he can do this, he meets Vic, a businessman with a proposal of his own; one that Kelso can't say no to. And Donna is upset that Eric hasn't contacted her from Africa yet.
Samantha uses her work experience to help both Kitty and Donna liven up their relationships. On Sam's advice, Donna has some "bedroom photos" taken of herself, intending to send them to Eric, but a series of mishaps puts the photos in a very incriminating place. Kitty takes Sam's advice, and tries some new moves on Red that result in a big change for both of them. Fez has his dreams of what having a roommate will be like, but finds that the reality is quite different.
Fez and Jackie become suspicious when they notice that Donna is spending an awful lot of time with Randy. Their less than stellar detective skills lead to trouble, and they learn an important lesson. Red learns some things himself, and this leads to an increase in his respect for Leo.
Bored with hanging around in the basement all the time, the gang looks for some fun elsewhere; Randy takes them to a local burger place where they have a lot of problems with the manager. Seeking revenge for being treated badly, Randy steals the mascot for the restaurant, Fatso the Clown. This puts him in the gang's good books, until things go horribly wrong.
While working at the hair salon, Fez meets a friend of Kitty's who is interested in more than just having her hair styled. When Kitty discovers that Fez is dating her friend, things get personal. Jackie, at a loss for what gift to get for Donna, goes looking through her room, and instead of finding an idea, finds out about Donna's latest crush.
Fez almost loses his apartment when Jackie floods it. He's ready to say "Good day!" to their co-habitation, but Jackie manages to salvage things by bonding with Fenton, the landlord, over shopping, and convincing him to let them stay. Red and Kitty are concerned over the number of arguments that Hyde and Samantha are having. But when they learn the reason for all the fights, it causes some sparks to fly in their own relationship.
Jackie meets the local star while at the salon with Fez: talk show host Christine St. George. Her new goal in life is to be Christine's co-anchor on "What's Up Wisconsin?", but breaking in to show business is harder than she thought it would be. She finally gets a job working with Christine, but it's not quite the job she wanted. Randy wants to take Donna away to a cabin, which makes her suspect his intentions; Red takes Hyde to his Lodge, and Hyde's intentions come under suspicion.
Jackie has some problems with her new boss, Christine St. George, whose constant demands keep Jackie frustrated. In an attempt to win her over, Jackie brings some of Kitty's home-made brownies to work. Her plan is successful, until Jackie takes credit for the brownies herself on television, and then finds that she now has an angry Kitty to contend with. Leo develops a crush on a younger woman.
Jackie is stuck in the lurch when a guest suddenly cancels their appearance on "What's Up, Wisconsin?" She needs to find a replacement, or else lose her job; so she and Fez take the place of the missing guest, pretending to be a couple in love. Christine is so impressed that she takes Jackie out for drinks after work, and spills some personal secrets, then fires Jackie for knowing too much. Donna has her eye on a special someone to ask out for Valentine's Day, but gets turned down. Red introduces Hyde to his secret stash.
Fez tries to impress a girl at the salon with his fantastic lifestyle, but Jackie sets things straight, blowing Fez's chances with the girl. He then sets out to create the life he dreams about with a little help from Isaac Hayes. Donna's relationship with Randy is taking off, and although she tries to keep it a secret, the gang finds out. Kitty gives Donna a box of old momentos of her relationship with Eric, which prompts her to have second thoughts about dating Randy.
Hyde's dad goes out of town and leaves Hyde with the responsibility of looking after his house while he's gone. The gang wants to have a party; the party gets a little out of control, and one of W.B.'s prized possessions is damaged. Kitty does some soul-searching and discovers the real reason behind her objections to Donna dating Randy.
Coming home from the local fair, Kitty's engagement ring accidentally goes out the window. Red leaves the kids on the roadside to find it while he takes Kitty home. While looking for the ring, Donna and Randy try to spend some time apart from the others; Fez makes a new friend after going off on his own. Once back in the comforts of home, Kitty finds out the truth about her ring.
Hyde finds out that his marriage to Samantha isn't quite what he thought it was when a man from her past shows up. Jackie makes a list of all the qualities that her dream-man should have and is surprised to find that he's been in front of her all along; Red decides to retire after an automotive shop opens nearby and takes away his customers.
Jackie turns to Donna for help; she needs to know what to do about her feelings for Fez, and ends up going to a therapist for advice. When Jackie finds out that she only loves men who are not available to her, she's happy... until Fez becomes available, and Jackie finds herself still wanting him. Hyde tries to help Red accept his new role as a retired man by keeping him busy around the house.
Jackie and Fez's love of The Village People inspires the rest of the gang to hold a "Disco Sucks" bonfire. While there, Fez meets a very friendly rocker chick, Donna meets some of Randy's ex-girlfriends, and Hyde meets the local law enforcement officer. Meanwhile, Red and Kitty meet their neighbors; Kitty's worried how Red will react to their lifestyle, but all that concerns Red is which football team they're cheering for.
Fez grows tired of dating girl after girl and realizes there is only one girl for him... crazy Caroline. Red returns home from the doctor with no problems, except for the fact that he's just spent two hundred dollars on heart pills that he no longer needs. So Red and Hyde decide to sell the pills to the guys at Red's Viking Lodge.
Bob returns from his Florida vacation with some startling news for everyone; Donna and Randy discuss taking their relationship to the next level, but Donna's having second thoughts. Fez and Jackie also encounter some problems with their relationship, which quickly escalate into all-out war.
WB sells Grooves, and after a celebratory circle, Hyde decides he needs a change of lifestyle. The gang is worried about Hyde's new outlook on life, but Hyde has yet another change of heart when WB announces that he's keeping the Point Place store. A friend of Fez's shows up to take him back home; the news that he might be leaving causes Jackie to realize that she has to make a move or lose him. Donna and Randy also come to an understanding in their relationship, while Red and Kitty show their house to prospective buyers.
December 31, 1979, and the gang is gathered at the Formans' house for one last New Year's Eve of the '70s. A party isn't a party unless the gang's all here... and some old friends return to celebrate the new decade, while some others get ready to leave.