“I will start at the beginning. When Miss Ackroyd asked me to investigate the case, I went up to Fernly Park with the good Dr. Sheppard. I walked with him along the terrace, where I was shown the footprints on the windowsill. From there Inspector Raglan took me along the path which leads to the drive. My eye was caught by a little summerhouse, and I searched it thoroughly. I found two things⁠—a scrap of starched cambric and an empty goose quill. The scrap of cambric immediately suggested to me a maid’s apron. When Inspector Raglan showed me his list of the people in the house, I noticed at once that one of the maids⁠—Ursula Bourne, the parlour maid⁠—had no real alibi. According to her own story, she was in her bedroom from nine-thirty until ten. But supposing that instead she was in the summerhouse? If so, she must have gone there to meet someone. Now we know from Dr. Sheppard that someone from outside did