The protagonist of this game is a young boy named Ken Ohsato, whose parents
were killed in a traffic accident. His father had worked for a big corporation
before he died; its owner, a very wealthy woman named Reiko Hayami, decides to
give the poor boy a new home. As Ken enters his new residence, he is
pleasantly surprised to discover that from now on he will share a house with
Mrs. Hayami’s five young and beautiful daughters. But not all is simple – soon
the young hero will find himself involved in complex relationships he would
actually prefer not to have…

Fatal Relations plays like a typical Japanese adventure. The player reads
text, views non-animated pictures, and chooses verb commands from a menu
(“Look”, Talk”, etc.). Navigation in the house is also performed by selecting
a specific location from a menu. Different cutscenes will be triggered
depending on where the player decides to go, and how he handles the various
encounters with the young women.