The player in this game is a retired hero of a human realm parallel to the modern world. The daughter is a girl from a royal heritage, and one of many candidates to assume the role of princess. However, following the assassinations of the other candidates, she became the target as well. Her entire family is killed during the attempt on her life. As her protector, Cube saved the player's daughter and requested the player to take care of the daughter until she reaches the age of 18. So the journey of parenthood unfolds with Cube's help.

[From Wikipedia]