SPOILER ALERT: the following article contains massive spoilers, including the ending. If you have not yet seen the movie, proceed at your own risk, or better, come back to this article later!
Siblings Clancy and Kevin discover that their seemingly normal mom is actually a former high-end thief in the witness protection program.
SPOILERS AHEAD
The Sleepover Plot Summary and Synopsis
In Boston, Massachusetts, Clancy Finch (Sadie Stanley) is invited by her crush Travis Schultz (Matthew Grimaldi) to a party at his house.
Her brother Kevin (Maxwell Simkins) is caught dancing in the restroom by some older students who record him dancing and bully him, but Clancy’s and Kevin’s mother Margot (Malin Åkerman), the lunch monitor, scares them away.
The bullies upload a remix video of Kevin dancing and Margot admonishing them to YouTube, where it quickly goes viral, gaining over two million views.
Kevin, Clancy, and her friend Mim (Cree Cicchino) are picked up by their father Ron (Ken Marino), an awkward pastry chef. Clancy asks her parents if she can go to Travis’s party and they both say no, leading to Clancy insulting her mother and getting grounded. Later, Kevin’s friend Lewis (Lucas Jaye) comes over for a sleepover in a tent in Kevin’s backyard. That night, Clancy and Mim sneak out to go to the party. They first scare the two boys causing Lewis to run into the house to pee.
While in the bathroom, he notices a man and a woman (Enuka Okuma) break into the house and force Margot (whom they call “Matilda”) and Ron to come with them under threat of death so that they can get their group back together. Lewis runs back to the tent and tells the others what happened.
Not believing him, the four run back inside until they notice United States Marshals Agent Henry Gibbs (Erik Griffin) sneaking into their house. Believing him to be an intruder, they attack him and tie him to a chair.
He tells the kids that Margot was in the Witness Protection Program because she turned in the crime boss of the crime syndicate she was in, but she has now been located due to the viral video.
They follow clues that Margot left them when she was taken away, leading them to a storage unit that turns out to be a secret spy center. They take a self-driving spy car to Travis’s party.
Travis agrees to take them to Downtown Boston in his family’s boat, but they are stopped by the U.S. Coast Guard and Travis has a revoked license. The four jump off and swim away, then reach the building where they believe their parents are located, but instead find a secret passageway behind a painting of Margot’s favorite poet W. B.
Yeats leading them to the hideout of Margot’s best friend Jay (Karla Souza), who tracks Margot’s GPS chip to an extravagant gala. Jay tells the kids to stay, but Clancy handcuffs her to a pipe so they can all leave.
At the gala, Ron, Margot, and Margot’s criminal ex-fiancé Leo (Joe Manganiello), who was also in the Witness Protection Program, are attempting to steal Queen Elise’s crown by poisoning her. When they meet her, Ron accidentally ingests the poison and vomits everywhere. The gala security then detains them.
When they are about to be sent to the FBI, Margot and Leo knock out all the security guards and they take Ron to the main floor, where they find Clancy, Kevin, Mim, and Lewis, who got in by pretending to be live musicians. The seven run away into Leo’s safe house.
At the safe house, Leo reveals that he was never in the Witness Protection Program. Instead, he is actually the new head of the syndicate as his associate Elise holds them at gunpoint and calls the police to frame them for the theft.
Ron throws a wolf spider at her to make her drop her gun and then uses it to shoot the chandelier onto her. Margot hot-wires a car that Ron uses to drive Leo into a bunch of construction barrels, then Margot kicks the crown out of his hands and Clancy then catches it.
The Sleepover Ending
The Boston Police arrest Leo and those involved. Henry drives everyone back to the Finch house where Travis returns Clancy’s jacket and Lewis’s mother picks him up. Everyone returns to their normal lives.
Source: Wikipedia (CC BY-SA 3.0).