The Case of the Missing Will

Hercule Poirot receives a visit from Violet Marsh, whose uncle, Andrew, has recently died. He had returned to England after making his fortune in Australia, and had then adopted her as a teenager, following the death of her mother. Despite his kindness, Andrew had opposed her efforts to pursue an education. Andrew's will stipulates that Violet may live in his house, Crabtree Manor, for one year, during which time she must "prove her wits" in order to inherit his estate. If she fails, it is to be donated to various charitable institutions. Poirot interprets the document as a challenge to find something that Andrew has hidden on the grounds – either a sum of money or a second will naming Violet as his heir.

Poirot and Hastings travel to the house and begin to search. Poirot notes that all the keys are neatly labelled except for the one to a roll-top desk, which is tagged with a dirty envelope. He questions Mr and Mrs Baker, Andrew's housekeepers, who state that they witnessed a will he had drawn up; however, he said that he had made a mistake and tore it up, then rewrote it with them as witnesses again. Andrew then left the house to settle some tradesmen's accounts. Poirot learns that Andrew had had a secret compartment built into the bricks of the fireplace, which proves to contain the burnt remnants of a will.

A defeated Poirot and Hastings begin the journey back to London, but Poirot abruptly insists that they leave their train and return to the house. Once there, he lights a fire in the fireplace, unfolds the envelope attached to the desk key, and warms it over the flames. It proves to be a second will written in invisible ink, dated after the one Violet was given and leaving Andrew's estate to her. Andrew had written two copies of the will Violet received, burnt and hidden one as a ruse, then written the one on the envelope with a tradesman and his wife as witnesses. Poirot comments that even though Violet did not find the will herself, her decision to ask for his help meant that she had outwitted Andrew in the end and thus deserved her inheritance.