El vendedor de globos de 78 años, Carl Fredricksen, lleva a cabo el sueño de su vida al enganchar miles de globos a su casa y salir volando rumbo a Sudamérica. Sin embargo, descubre más tarde que no va solo, ya que también se ha embarcado en el viaje Russell, un optimista explorador de 8 años.
Sinopsis en inglés:
In order to get away from their busy lives, the Wilson family takes a vacation to Santa Cruz, California with the plan of spending time with their friends, the Tyler family. On a day at the beach, their young son Jason almost wanders off, causing his mother Adelaide to become protective of her family. That night, four mysterious people break into Adelaide's childhood home where they're staying. The family is shocked to find out that the intruders look like them, only with grotesque appearances.