Flint Lockwood (Bill Hader) always wanted to invent something awesome. He grew up with his first invention being "Spray-on Shoes", which unfortunately imprisoned his feet for life, and led to people already making fun of him at a young age. As he grows the rest of his experiments seem to have a downside to them as well, such as "The Flying Car", a television with legs, and "ratbirds." Flint believes he is a failure, but his mother Fran Lockwood (Lauren Graham) always believed he can succeed. However, she passed away later, leaving him with his father, Tim Lockwood (James Caan). Flint lives in a small island town called Swallow Falls, hidden under the "A" in "Atlantic", which is famous for sardines. However, when the town’s economy fell, it left the town in hard times, leaving sardines as the only food in Swallow Falls. Flint finally comes up with an invention that converts water into food called the Flint Lockwood Diatonic Super Mutating Dynamic Food Replicator (FLDSMDFR for short), but he doesn’t have enough electricity to get it working. Tim discovers Flint’s new failure and suggests he should quit working on experiments to work with him in his fishing shop. However, the next day, after Flint finishes his unpleasant shift, he and his pet monkey, Steve (Neil Patrick Harris), who communicates with a thought translator, try to charge up the machine using the power station. Meanwhile, Mayor Shelbourne (Bruce Campbell) along with ‘Baby’ Brent (Andy Samberg), the towns’ sardine celebrity mascot and Flint’s school bully, opens a new theme park called Sardine Land, in hopes it will make him widely recognized. Sam Sparks (Anna Faris), a weather intern from New York City has her big break reporting these events with her cameraman Manny (Benjamin Bratt). When Flint powers up the machine, the machine goes haywire and zooms through the theme park and up into the air with Flint attached, causing maximum damage to Sardine Land right as it opens.Humiliated, Flint flees to the docks where he meets Sam, while the sky starts to rain cheeseburgers from giant purple clouds all over the island. Flint finds it is the FLDSMDFR, which is still in the sky and takes Sam to his lab. He keeps her occupied by having her watch a video of a kitten and ducklings singing “Fight the Power” as he builds a communication device that allows him to send orders of food to the FLDSMDFR. People begin to praise Flint’s invention and ask him for requests of food to rain down, like ice cream for the town’s nearly superhuman cop, Earl’s (Mr. T) son, Cal’s (Bobb’e J. Thompson) birthday, and a giant Jell-O mold for Sam while on a date with her (of which Flint has a horrible time trying to ask her out on). He also builds the Out-Of-Sigher, a device that launches the leftovers on the ground behind a "nearly indestructible" dam, Mount Leftovers. The town is then renamed Chewandswallow and the mayor plans a grand re-opening of the town hoping the food weather will attract plenty of tourists, which will make him more recognizable than ever before.While on a date with Sam, Flint discovers a lot about her, like her allergic reaction to peanuts, but more importantly that she was once a “nerd”. She was a “nerd” for the weather, and she wore her hair back and large glasses. She changed her look later in life to get away from criticism, but Flint likes her the way she was, and Sam agrees to go out in public with the look after he gets her to put her glasses on and tie her hair back. Right before leaving, Flint nervously (and awkwardly) tries to kiss Sam but gets interrupted by a phone call. The call is from Mayor Shelbourne, asking Flint to cut the ribbon at the town’s grand re-opening. Afterwards, Flint runs into problems with his father, who can’t admit that he is proud of his son, and Flint storms off angry and disappointed. He then comes across giant hot dogs, realizing that the food is starting to rain in large quantities. Noting that the food molecules are mutating, Flint goes to turn off the FLDSMDFR, but the Mayor (who is now morbidly obese from all the food he ate) deceives him and says he shouldn’t and no one would like him anymore if he did. Flint, realizing this is the only time people weren’t scolding him for a mishap, orders spaghetti for the next day’s menu for the tourist’s arrival to town at the grand re-opening. But meanwhile in the sky, the FLDSMDFR grows mold on itself, and an eye appears on its screen.Then the next day at the town’s grand re-opening, the spaghetti forms a twister, which proves that the food is starting to mutate. Flint goes to turn off the FLDSMDFR, but the Mayor is seen ordering a Vegas-style buffet, and accidentally destroys the communication device. Sam, using her weather computer tries to warn the world through the news that a life threatening food storm will strike, but they disconnect her off the air at first for her "nerdy" appearance. Luckily she gets re-aired and warns everyone about the events that could destroy the world. Flint gives up believing he truly is a failure, but his father finally talks to him and encourages him to save the town. Flint puts a kill code in a USB Drive then builds “The Flying Car 2 with wings” and Steve, Sam, Manny, and ‘Baby’ Brent (Brent going along trying to find a new "self image" since his old one was destroyed after Flint became famous) give a chase to the FLDSMDFR, while the citizens and tourists build sandwich boats to escape to the sea.The FLDSMDFR has formed a giant meatball around itself and Flint, Sam and Brent enter the meatball while Manny and Steve stay behind in the car. Flint loses the USB Drive on the way and calls his father to send the kill code to his cellular phone. Tim hesitantly enters Flint’s lab, and has trouble following through with what Flint told him. While finally sending him the kill code, Mount Leftovers collapses and covers the town with massive amounts of food, and it seems that Tim had been crushed, but he successfully pulls himself out and sends the kill code to Flint’s phone. Flint, Brent, and Sam then uncover sentient food which has undergone large mutations for it to be able to protect the FLDSMDFR on their own, and fight their way through giant man eating baked chickens. Brent is seemingly eaten by one, but is able to control the chicken and fight the rest off alone as his new self, ’Chicken’ Brent. Flint and Sam then head off alone but Sam must leave Flint after having an allergic reaction to peanut brittle. Now alone, Flint encounters the FLDSMDFR, while Sam and Brent escape with Manny and Steve. Flint jams the phone into the machine to release the code, however it appears that Tim sent him the wrong document, the video of the kitten and ducklings singing “Fight the Power”. The FLDSMDFR fights back physically, but Flint covers the food extraction hole with his Spray-on Shoes spray. The FLDSMDFR and the meatball explode, and the purple clouds around the world disappear. At the town, which is covered by giant food, Sam, Steve, and Brent arrive unharmed. Seeing Flint is not with them, Tim and the other citizens mourn to Flint whom they believe is dead, but Flint returns unharmed, saved by the ratbirds he created.. His father finally admits his proud feelings and love to his son, and Flint and Sam finally kiss.During the end credits sequence, Flint and everyone else enjoy their new life in a food paradise, renamed Chewandswallow 2. Tim and Flint open up a new business that uses Flint’s Spray-on Shoes spray to repair roofs, and the Mayor is arrested and jailed by Earl and Cal for his greedy behavior.