Hastings tells Poirot about a new restaurant opening in London which has the same name as one Poirot visited two years ago in Buenos Aires. A yellow iris arrives with the post, which further reminds Poirot of his trip. Iris, one of his dinner companions in Buenos Aires, was murdered and Poirot was unceremoniously deported before he could investigate. Could the mysterious arrival of the flower be a request for Poirot to pick up the case again?