Two teams touch down at the STARS space station to take on three scientific challenges to win out-of-this world prizes. First, they must work out if an object is heavier or lighter than another before placing it on a giant set of scales. Then the young scientists have to complete a huge fossil by digging for dinosaur parts in ball pits. Finally, the teams must make their way across a giant inflatable version of the solar system. Can they get from Neptune to Mercury by stepping on every planet in the right order without getting knocked by the swinging stars?Meanwhile, Ayo and Sam learn about the importance of exercise to keep our bodies and minds healthy.