Mrs Hudson forces Holmes and Watson to settle a trivial feud. They embark upon an eventful railway journey to Ross-on-Wye where Inspector Lestrade is on the case of a brutal murder, which has taken place near a lake surrounded with dog turds. Lestrade has made some obvious conclusions to make a water-tight case against a young man but Sherlock Holmes dives into the undercurrent of local society and discovers a string of old relationships that tell a different story.