The Decagon House MurdersJukkakukan no Satsujin ; 十角館の殺人 ; Los Asesinatos de la Casa Decagonal ; Los Asesinos de la Casa Decagonal ; คดีฆาตกรรมคฤหาสน์สิบมุม

Students from a university mystery club decide to visit an island which was the site of a grisly multiple murder the year before. Predictably, they get picked off one by one by an unseen murderer. Is there a madman on the loose? What connection is there to the earlier murders? The answer is a bombshell revelation which few readers will see coming.