Uncle Buck is a 1989 John Hughes comedy film starring John Candy, Amy Madigan, Jean Louisa Kelly, Gaby Hoffman, and Macaulay Culkin, and co-stars Jay Underwood and Laurie Metcalf.
Bob Russell (Garrett M. Brown), his wife Cindy (Elaine Bromka), and their three kids, 15-year-old Tia (Jean Louisa Kelly), 8-year-old Miles (Macaulay Culkin), and 6-year-old Maizy (Gaby Hoffman) have recently moved from Indianapolis to Chicago due to Bob's job promotion. Tia resents her parents for the move because she thought everyone was happy enough where they were already living and that they prefer their jobs to the family.
Late one night, Cindy and Bob receive a phone call from Indianapolis informing them that Cindy's father has suffered a heart attack. The couple makes plans to leave Chicago immediately to be with him. Upon being told the news, Tia angrily accuses Cindy of abandoning her own father.
Unable to find an adult to watch the children, Bob suggests they ask his brother Buck (John Candy) to do so, something Cindy rejects. While Bob and Cindy are decidedly upper middle class suburbanites, the gambling addicted, unemployed Buck lives in a working-class apartment in Chicago, drinks and smokes frequently, earns his living by betting on rigged horse races and drives a hideous, backfiring, 1978 Mercury Grand Marquis (nicknamed "The Beast"). Cindy also does not approve of his girlfriend Chanice (Amy Madigan), who has a car repair business. As no one else is available to help them, Bob and Cindy have no choice but to turn to Buck, who agrees to help his brother and sister-in-law.
Buck immediately hits it off with both Miles and Maizy, but Tia is suspicious of Buck. Upon taking her to school, Buck meets Tia's boyfriend Bug (Jay Underwood). Buck immediately recognizes that Bug's only interest in Tia is for sex, and warns his niece, who doesn't believe him. Buck repeatedly thwarts her and the two frequently trade snide wisecracks and engage in a battle of the wills.
Over the next several days, Buck deals with a number of situations involving Chanice, Tia, Miles, and Maizy. These include taking the kids to Buck's favorite bowling alley, making gigantic pancakes for Miles' birthday, dealing with a drunken clown, and talking to a school counselor about Maizy. In these situations Buck is shown to be a kind, sensitive, well-meaning man in spite of his laziness and boorishness. His personal ethics are tested when he nearly takes the younger children to a racetrack to bet on a rigged race.
However, Tia doesn't like that Buck is trying to keep her away from Bug. When Buck again scares Bug with a hatchet (telling Bug he wants to show him it), Tia makes Buck's girlfriend think he's cheating on her with their neighbour (Laurie Metcalf). After that, Tia sneaks away with Bug to a party. Worried and concerned about Tia, Buck decides not to attend the horse race, and find Tia instead. Buck locates the party and eventually Bug. Thinking Bug is taking advantage of his niece in a bedroom at the party, he drills a hole through the door knob and walks in on Bug with another girl. Realizing that Tia had already left using her own better judgment, Buck ties up Bug and throws him into the trunk of his car. After commiserating with Tia, he lets the boy out of the trunk to apologize to Tia for his behavior. When he is finally released, Bug takes back the apology as he flees from them both. Buck begins striking him with golf balls and chasing him away. Buck, who has been unable to commit to marriage, finally realizes what he has been missing.
As Cindy returns home when her father begins recuperating, both Tia and Cindy resolve their issues. Tia and Buck share a smile and a wave before he returns to Chicago to eventually begin work at his girlfriend's business.
At post credits, Buck's voice shouts "Wake Up!"