りら荘事件

6 students visit Villa Lilac to spend their summer vacation when suddenly superintendent Yuki shows up and informs them about the corpse of a man wearing one of the students raincoats who was found under a cliff near the mansion with an ace of spades lying next to him. This incident is only a forewarning of a series of murders yet to come, each one attached with a new card and clouded in alibis. The police find themselves in a dead end which forces them to get the help of "amateur" detective Hoshikage Ryuuzou.