Kamen Rider Gaim takes place in a certain booming city that a large corporation controls like a "castle town" from feudal days. Bored kids in this town begin to express themselves by participating in street dance. Among these kids, there are some who use Lock Seeds in order to summon monsters called “Invase” to fight as a game. The Invase come from another world through a door that opens when the game begins, but due to more doors being opened in various places, the world is put in great peril. In this world, series hero Kazuraba Kota and other rival Kamen Riders fight the Invase with fruit-themed weapons.