To stimulate interests in online RPG.

A player A of a video game machine 103a requests a player B of a video game machine 103b connected to the machine 103a through a game server to call a player character. If the player B selects 'YES' (step S602; YES), the game server, upon receiving that selection, generates screen data, in which the play character of the player B appears, in the screen of a scene, in which a play character of the player A exists, thereby transmitting the screen data to the game machines 103a, 103b (step S503). Upon receiving the screen data, the game machines 103a, 103b display, based on the screen data, a screen in which the play character of the player B appears in the scene in which the play character of the player A exists (steps S407, S604).