Sherlock Holmes: The Devil's Daughter

Near the beginning of the ‘Infamy’ case, after you are introduced to Orson Wilde, you will be visited by a young woman named Mary Sutherland. She is trying to find her suitor, Hosmer Angel. After she sits down, complete her character portrait before asking her any questions. At one point during the dialogue, she will reveal that Mr. Angel is missing and has submitted a missing persons notice in the newspaper. Holmes will ask for this and will also be given a letter from Mr. Angel.

After reading the letter, look over it in detail for any abnormalities. After finding some typographical defects, Holmes asks if Miss Sutherland has any other letters from Mr. Angel. She does not but has a letter from her father. Again, look over the letter and again Holmes will find some typographical defects. After comparing the letters and forming a deduction, you will be asked to make a moral choice. After you select one or the other, the achievement will unlock.

This achievement starts at [3:30] in the case walkthrough video in “Lock, Stock, and Two Smoking Detectives.”