A diverse group of Spanish tourists on a planned trip, a once-grand hotel crumbling into ruins, and a handful of dark secrets converge during a week-long holiday in Lisbon. When one of the travelers is found dead the day after their arrival, four of the others set out to investigate who the killer might be—and whether it could even be someone within their own group. This team of devoted true-crime and mystery-novel fans will have to face the police, a roster of suspects, the threat of being expelled from the trip, and their own hidden truths as the days slip away before they have to leave Lisbon.