The hero of this game is an ordinary high school student (the player has to name him by himself). He is mostly interested in pretty girls, in particular the lovely Mika, with whom he is even ready to discuss books just to get her attention. One day, a beautiful woman appears in front of him out of nowhere. She says that she is Venus, the goddess of love. She comes from a world called Cal, the eternal world populated by lovely girls. She tells the hero that soon he will be needed in that world... and disappears. Was that a dream? Or will our hero really travel to the magical world of Cal and encounter dangers he hasn't even imagined before?
Cal is a visual novel, with the sole interaction consisting of choosing sentences to say and sometimes actions to do from a context-specific menu at the bottom of the screen. Usually only one such selection triggers the next event; some choices lead to Game Over. The game contains erotic pictures with nudity and sexual situations.