A late-night telephone call summons Hercule Poirot to the Jardin des Cygnes, a fashionable restaurant where he is told to find the table decorated with yellow irises. The voice belongs to a woman in distress, and by the time Poirot arrives she is nowhere to be seen. At the table sits a dinner party hosted by a wealthy American, gathered to mark a grim anniversary: years earlier, his wife Iris died of cyanide poisoning during an evening that this one deliberately echoes. The same guests have been assembled, the same flowers chosen, the same music and dimmed lights arranged, as though the host means to summon the past back to the present. Poirot, an uninvited stranger at the table, studies the small circle of diners and their tangled loyalties, watching for the moment when the carefully staged re-creation tips toward danger. As the lights fall and the band plays, the threat that has hung over the party finds a new target, and Poirot must read the meaning behind a glass, a sequence of movements, and a single yellow flower. Working with only minutes and a few sharp observations, he tests who is acting from grief and who from calculation. This compact case turns on misdirection and timing, building toward a quiet, precise unraveling that depends less on physical clues than on understanding exactly what one person at the table intends to do.