In the year 2050, thirty young cartoon characters win a free copy of the latest VRMMORPG, Weapon Fantasy (ウェポンファンタジー, Uepon Fantajī). Hopper the Frog, who goes by the nickname "Kero", is one of those winners. Using a virtual reality helmet with nerve control (the ability for the helmet to control all five senses), the users must complete all fifty levels before reaching the final boss. It is possible to save the game and log out at any time. However, if a player loses the game, the user is then erased (literally) from existance. If Kero has to win the game, he and his guild must survive, or it will be game over for them.