| Director | Bob Hoskins |
|---|---|
| Genre | children's film, fantasy film |
| Country | United Kingdom |
| Budget | $10 million |
Mike "Mikey" Bailey is a rambunctious boy living in Hudson Harbour, New Jersey with his grandfather Frank, a magician; his single mother Jackie, who works in the newsroom at a local TV station; and his older brother Steve, who is a loner and wishes to join a local gang of teenagers. Mike encounters a stray dog who he names Mutt, who leads him to a spot where he seemingly witnesses a rainbow actually land. He tells his friends Pete and Tessy of his encounter and takes them to the landing site, but they do not believe his claims. At the site they find a triangular crater. Tessy takes a soil sample and tests it, and the soil illuminates in colour and vanishes in her hand. Mike, Pete, and Tessy prepare a project to track down the next rainbow and examine it.
Eventually, a rainbow appears and the three, along with Steve and Mutt, race across town on their bicycles to get to the rainbow. Upon arrival, they witness it land and are sucked into a colourful passageway, taking photographs as they go. They are surrounded by sparkling lights, when turn into pieces of gold when touched. Steve pockets three of the pieces, which causes the rainbow to vanish and drop the group into a cornfield in Kansas. The farmer takes them to the office of sheriff Wyatt Hampton, who calls Jackie at work to make arrangements to send the kids home. The sheriff takes the kids to the airport, where they sneak away to get their pictures developed and lead the sheriff on a wild chase before boarding their flight. They arrive back in Hudson Harbor, where they are mobbed by reporters who had been tipped off by Jackie's boss. Jackie and Frank come to the children's aid, but everyone except Frank thinks the kids had stowed away on a flight to Kansas are lying about the rainbow. They get in trouble at school and turn the photos they took over to their science teacher, Sam Cohen.
The next day, colour begins to drain from the world, and people begin to either act aggressively towards each other or fall unconscious. Sam realizes that there weren't any flights that could've taken the children to Kansas in time, and after looking at their pictures, discovers their project and finds the crater. Steve sells one of the pieces of gold to a pawnshop, and uses the money to buy a motorcycle and leather jacket, and tries to use another piece to buy his way into the gang, but they gang beat him up and steal the bike, jacket, and gold from him.
The children, Frank, Jackie and Sam all deduce that due to Steve's removal of the gold pieces, the rainbow has been damaged and caused colour to be drained from the world, preventing plants from generating oxygen through photosynthesis. The group split up to retrieve the gold pieces. Mike and Frank break into the pawn shop and retrieve a piece of the gold, barely escaping the violent mobs roaming the streets. Steve, Pete and Sam go to the gang's hideout, which they fill with helium as a distraction so Steve can steal back his stuff. With time almost up before all the oxygen is gone from the world, Mike, Steve and Mutt race on his motorcycle through the violent mobs to the new rainbow's landing site. Mike and Mutt are absorbed by the rainbow, but Mike tosses the gold pieces back into it, causing a rain which restores color to the world. Mike and Mutt ride the rainbow to a tropical rainforest, as the film ends.