The ravishingly beautiful bride Lady Lucy Atterberry lies dead on the shores of Lake Weidenhof. None of the noble British wedding guests claim to have noticed the murder. How fortuitous that Achille Perrot, grandson and only descendant of the renowned Hercule Poirot, is among the guests. Along with Inspector Jeff, who relocated to Lower Saxony out of his love for a woman, he sets out in search of the murderer in a labyrinth of lies and half-truths.
Contrary to the numerous suspects among the wedding guests, there is a lack of evidence. Is this perhaps due to Inspector Jeff's soft spot for mahogany brown eyes? The investigations turn out to be increasingly mysterious. But when another murder occurs, Perrot follows this new lead and comes across treacherous goings-on in remote masonry.