The Yellow Iris

A yellow iris arrives for Poirot, and the flower means trouble. Two years earlier, in Argentina, he watched a woman die of cyanide poisoning and could not solve the case. He recognised the flower at once, which is the first clue to how badly the case stuck with him. Now her husband is marking the anniversary of her death, and somebody is letting Poirot know the matter is not closed.

The episode is a return trip to that earlier evening, in memory and in fact. The faces are the old ones, wearing the same polite smiles, and the story that slipped through his fingers the first time is laid out for him again. Watching Poirot pick at a memory is the appeal of the piece. He is not used to being the one who missed it. And he carries the old case like a stone in his shoe. A second chance at a case that beat him is not something Poirot is built to refuse.

Anthony Horowitz and Agatha Christie wrote it, Peter Barber-Fleming directed. David Suchet is Poirot, with Hugh Fraser as Hastings and Pauline Moran as Miss Lemon. David Troughton plays Barton Russell, Dorian Healy Anthony Chapell, Geraldine Somerville Pauline Wetherby, Yolanda Vazquez Lola, Robin McCaffrey Iris Russell, Hugh Ross Stephen Carter and Joseph Long Luigi.

It is a quiet episode in the best way, and it trusts one remembered evening to carry the whole mystery. The yellow iris is a summons. Poirot treats the case like an unpaid debt, because it has followed him for two years and it is time to settle. This is an old case being finished, and the difference shows in every careful step. The flower, when it comes again, is both the invitation and the accusation. He wants to put it right, and the episode gives him the chance without making it easy.