Super Sentai Series Choushinsei Flashman

In 1966, five children were kidnapped by an alien group known as the Alien Hunters, for the sake of the Reconstructive Experiment Empire Mess, who wanted samples of humans from Earth to experiment on. They were rescued by the Flash alien race, each one of the five rescued children was taken to a different planet of the Flash solar system for training. Each of them was trained separately from the others in a range of superpower abilities which would will allow them to fight the Reconstructive Experiment Empire Mess. When they finally returned to Earth in 1986 to combat Mess, who are now trying to invade, they use the opportunity to search for their birth parents. It is later that they learn they can only stay on Earth for one year before the now-alien atmosphere of their true planet will physically harm them.