The Sign of Four

Plenty of racism, and honestly the plot is pretty stupid. Not Sherlock's best outing. But five hearts for the story of Watson getting all smitten and acting dumb around his wife-to-be.

ETA: I'm adding back one more star for the fabulous quote: “‘My mind,” he said, “rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram or the most intricate analysis, and I am in my own proper atmosphere. I can dispense then with artificial stimulants. But I abhor the dull routine of existence. I crave for mental exaltation.”