Los asesinatos de la mansión decagonal, 1

On the island of Tsunojima, a renowned and eccentric architect has a luxurious decagon-shaped mansion built in which, some time later, he appears brutally murdered along with his wife and two servants. Half a year later, a group of seven university students, members of the mystery club, attracted by the unsolved enigma and the particularity of the case, decide to spend a week on the island to investigate the murder. However, upon their arrival, they will soon begin to sense a threatening presence lurking around them and it will be clear that someone wants to kill them off in the most devious way possible.