In X-Change the player takes the role of Takuya Aihara, an average guy who lives with his father and stepmother, goes to school, and is not really noticed by anyone - until one fine day he accidentally spills on himself a mysterious liquid in a chemistry lab. The liquid turns him into... a girl! Now everybody notice Takuya, and everybody "want" him/her. The question is, will he rather stay like this or return to his normal male self?
This is what the player will have to decide in this game. It is possible to make Takuya an uncontrolled nymphomaniac, or try to do everything in order to help him get his original gender back. Like most other adult visual novels, the game's story development depends on the choices made by the player during its course. There are two main endings and many smaller ones, which are classified as unsatisfying.