An old general is murdered in his home by a mysterious visitor who quickly vanishes from the scene of the crime. Holmes and Watson investigate to see whether the crime was due to the general's part in a Veteran Tontine, a book he was writing on a missing diamond, a disgruntled marriage, or something hidden deep in his past. Source: Wikipedia, "[en.wikipedia.org/wiki/Sherlock_Holmes%3A_Consulting_Detective Sherlock Holmes: Consulting Detective]", available under the CC-BY-SA License.