The king is getting old and has no heir to give the kingdom to. In order to decide the next ruler, a competition has been put in place called "The King's League." Recruit troops and train them so that you will win the tournament and become the next heir to the kingdom.
Start in an empty black room and use your paint gun to mark walls, dangerous spikes, and eventually get a picture of the level layout. Navigate through each level and find the magic paint box while using as little paint as possible.