The movie rotates around a lonely old widower named Carl Fredricksen. He lives all by himself in a house and is haunted by property developers who are pestering him to sell his land.
Finally unable to take it no more the old man is pressed to retreat by tying thousands of multi-coloured balloons to his house to conquer a childhood dream: visiting the legendary Paradise Falls in Venezuela. Just when he was setting off on his adventure he discovers with dismay that he had even brought along a feisty boy scout named Russell who had been hanging around the house while it was carried away by the wind.
A relationship filled with amusing, sweet and touching moments develops between the grumpy Carl and overly eager-to-please Russell. The pair is later joined by Dug, a dog who is able to make his thoughts heard by using a vocal device on his collar and Kevin, a mysterious and colourful bird.
