You were playing Jump Ultimate Stars on your DS, but you suddely wake up on a strange place. You look around and see flying lands everywere and green tall grass all around you, you look up and see peoples flying together and various Capsule houses

After that you see a boy/girl looking to you on top of a tree with a Dragon Radar. by her side was Jump Pirate, the mascot of Shonnen Jump, Jump Pirate comes closer and say

Jump Pirate: Welcome to J-World, Human! You are our last hope!~