Minions are small, yellow creatures who have existed in the beginning of time, evolving from yellow single-celled organisms into beings which exist only to serve history's most evil masters. After rolling a Tyrannosaurus into a volcano, getting their caveman leader eaten by a cave bear, crushing a Pharaoh under a pyramid after constructing it upside-down, exposing Count Dracula to sunlight, and accidentally firing a cannon into Napoleon while in Russia, the Minions drove into isolation and start a new life in a massive cave. After many years, the Minions become depressed and unmotivated without a master to serve. To regain their dignity and sense of purpose, Kevin recruits Stuart and Bob, setting out to look for a new master.
In 1968, the three journey to New York City, where they end up in a department store for the night, and accidentally discover a hidden commercial broadcast for villains advertising Villain-Con; a convention for all villains and supervillains in Orlando. The three eventually hitchhike a ride with the Nelson family and impress them with their accidental villainy after being chased by police as a result of a robbery committed by the Nelsons. At the convention, they see Scarlet Overkill, an incredibly famous and popular female supervillain who unexpectedly hires them and takes them to her home in England. They phone the rest of the Minions to get them to join. Scarlet uses the plan to steal the Imperial State Crown from Queen Elizabeth II and promises to reward the Minions if they steal it, and kill them if they do not. Her husband, Herb, supplies them with inventions to aid in the heist, but they are nearly caught when they break into the Tower of London. The chase leads to Bob accidentally crashing into the Sword in the Stone by pulling it free to defend himself and his friends, causing Bob to remove the Queen from the throne and becoming the King Bob. Enraged that somebody else accomplishes her dream of stealing the throne, Scarlet confronts the Minions, so Bob abdicates the throne in her favor. Undeterred, Scarlet imprisons the three in a dungeon before her coronation and Herb tortures the trio, but they escape with the intention to apologize to Scarlet.
After making their way to Westminster Abbey, Stuart and Bob interrupt the coronation by inadvertently dropping a chandelier on Scarlet, who catches them, and orders their execution having survived. Dozens of villains chase the three of them during a thunderstorm; Kevin goes into a pub, where the Queen hangs out. He sees Scarlet on a television, promising that she will kill Stuart and Bob if Kevin does not show up by dawn. With the villains still searching for him, Kevin sneaks into Scarlet's castle to steal weapons, and accidentally triggers a machine Herb was building and grows into a gigantic minion, destroying the castle. Kevin tramples through London, rescues his friends and battles Scarlet just as the other Minions turn up in London. Scarlet tries to eradicate them by firing a massive missile, and Kevin swallows it. Scarlet and Herb attempt to escape with her rocket-dress only for Kevin to hold into it and get pulled into the sky. The missile finally explodes, seemingly killing Kevin, Scarlet, and Herb. As the Minions mourn the loss of their leader, Kevin survives and was shrunk back to his normal size.
The Queen gets her throne and crown back. She rewards Bob with a tiny crown for his teddy bear, Stuart with an electric guitar, and Kevin with a knighthood. Scarlet and Herb, who have also survived the explosion, steal the crown for themselves once more, but they are frozen by a young Gru, who flees with the crown on a rocket-powered motorbike. The Minions stare in awe and run after Gru.
Pierre Coffin as Kevin, Stuart, Bob, and the Minions
Sandra Bullock as Scarlet Overkill
Jon Hamm as Herb Overkill
Michael Keaton as Walter Nelson
Allison Janney as Madge Nelson
Steve Coogan as Professor Flux and the tower guard
Jennifer Saunders as Queen Elizabeth II
Geoffrey Rush as the narrator
Steve Carell as young Gru
Katy Mixon as Tina
Michael Beattie as a VNC announcer and Walter Jr.
Hiroyuki Sanada as Sumo villain
Dave Rosenbaum as Fabrice
the spin-off prequel and the third installment overall in the Despicable Me franchise