The Adventures of Elmo in Grouchland is a 1999 children's film produced by Columbia Pictures.
Ernie and Bert introduce the film, and Elmo welcomes the viewer, finds his blanket and plays with it in his bedroom. He spills juice on his blanket and takes it to the laundromat where he encounters his friend Zoe. Elmo refuses to share his blanket resulting in a tug of war that rips it. an irritated Elmo declares that Zoe is no longer his friend.
Telly Monster, rollerskating out of control, accidentally swipes the blanket leading to a chase around Sesame Street. The blanket falls into the hands of Oscar the Grouch, who drops it in his trash can. Elmo dives into the bottom of Oscar's can, where he finds his blanket snagged on a door.
Attempting to retrieve it, he and his blanket are teleported through a colorful swirling tunnel to Grouchland, a city filled with Grouches, garbage, and Huxley, a greedy man who steals anything he can grab, including Elmo's blanket. A kind Grouch girl named Grizzy tells Elmo that his blanket is in Huxley's house at the top of the faraway Mount Pickanose. A plant named Stuckweed encourages Elmo that he will make it if he just takes his first step, so Elmo sets out on a quest to retrieve his blanket.
With Oscar's help the Sesame Street residents go to Grouchland to find him. They ask a Grouch police officer for help but are arrested and imprisoned.
Huxley has his sidekick, Bug the bug and his minions, the Pesties, trap Elmo in a tunnel. Elmo gets out with the help of fireflies. Huxley then has Bug and the Pesties misdirect Elmo into a garbage dump where he is brought before the Queen of Trash for trespassing. The Queen tests him, requesting that he blow 100 raspberries for her in 30 seconds.
Elmo succeeds with the help of the audience and the Queen allows him to pass through. Huxley sends his huge chicken to stop Elmo, who tosses Elmo far away. Elmo gives up on retrieving his blanket for the night.
Meanwhile, Grizzy sneaks into the jail where she informs Elmo's friends that he went to Huxley's house. Oscar convinces all of the Grouches to cooperate, as it is the only way they can stop Huxley from stealing any more of their trash. The police officer releases the Sesame Street residents and the Grouches aid them into the night to go to Huxley's house to fight for their trash and rescue Elmo.
A caterpillar wakes Elmo the next morning. He convinces Elmo that he has what it takes to be brave. Elmo arrives at Huxley's house as Huxley sends the Pesties to stop him. The Sesame Street and Grouchland citizens arrive and the Pesties flee in panic.
Huxley sucks up Elmo's blanket with the vacuum cleaner nozzle on his helicopter. Elmo launches a basket over Huxley's shoulders, incapacitating him. Bug is at the controls of the helicopter and refuses Huxley's demand for it back as he is sympathetic to Elmo and instead gives it back to him.
Elmo returns to Sesame Street with his friends, where he apologizes to Zoe and allows her to hold his blanket. She accepts his apology, agreeing that they can resume their friendship. Elmo says goodbye to the audience and thanks them for helping and goes to dance with his friends.