You are playing as a middle age Gentlemen who loves to go out. He met this gorgeous young woman (bar lady) which he hook up with but she isn't normal, she is a psycho girl who don't want to share her man, after the one hook up she became obsess with him and bewitched him.
In order for you to be able to install this game, you need to enable (allow) installation of applications from unknown sources (Unknown sources) in the phone settings. Usually this item is in the Security section