Harlowe. During the split-second that the light was on, she noted the clock on the opposite wall: it showed 10:30. Not wanting to intrude, she returned to her own room. When the door seals are removed, Hanault is able to search the treasure room and bedroom. The clock is found to be accurate to the minute, but the arrow is not there. Jim stumbles across it later in Ann's room, converted to a pen. Following up Waberski's story, Hanaud and Jim track the herbalist Jean Cladel down to a seedy part of town. But they are just too late: he has been stabbed to death. When Ann receives an anonymous letter bidding her attend a ball where she will learn the truth about Mrs Harlowe's death, Betty encourages her to go. Ann is kidnapped, bound, and taken to an empty house nearby where she is confronted with the murderers: Betty and her maid Francine. As Betty approaches Ann with a hypodermic syringe of arrow poison, Hanaud steps out from his hiding place. He had suspected Betty for some time, he later tells Jim, but unable to prove her guilt had allowed the kidnapping to go ahead to secure hard evidence. The key to the mystery had been Hanaud's realisation that Betty continued to have access to the treasure room, in spite of the sealed doors, via a secret passage running from an old sedan chair in the room to the nearby empty house. The murder, which had indeed been heard by Ann, took place after Betty's return, at 1:30am. The clock which had apparently read 10:30 was showing the correct time, but had been seen in a mirror. Betty took advantage of the mistake, and before the room was unsealed she moved the clock so that it stood in direct line of sight opposite the door. The arrow had been in the room, but after Hanaud had drawn attention to the monograph Betty had re-hidden it to implicate Ann. Principal characters Mrs Harlowe (née Jeanne-Marie Raviart), a wealthy widow Betty Harlowe, Mrs Harlowe's niece Boris Waberski, Mrs Harlowe's brother-in-law Ann Upcott, companion to Betty Harlowe Francine Rollard, maid to Betty Harlowe Jean Cladel, a herbalist Monsieur Bex, local notary to Mrs Harlowe and Betty Jim Frobisher, English solicitor to Mrs Harlowe and Betty Inspector Hanaud of the Paris Sûreté Background According to the author himself, the book was inspired by