John isn't an idiot, but some things just take him longer to work out. He's not Sherlock or Mycroft or Mary. Set beginning the day His Last Vow ends. John/Sherlock, John/Mary. See tags for warnings.
"The breakdown: 35. Canuckian. ESL professor. Choir conductor. Former/now part-time classical singer. Writer. Extreme Geek. Diehard Johnlock shipper. Not a fan of Mary, at all. Firm believer that Mary needs to face justice for her many crimes and to do it elsewhere, and the sooner her departure comes, the better."
This was the first Season 3 "fix it" fic that SilentAuror wrote, and I think Act IV, Shallow Grave, and especially Vena Cava are superior, but this is still a good fan fic.
John tries to figure out what's going on with Mary and Sherlock when no one will tell him the truth. This has something of a "case fic" feeling, because it's John figuring out what Mary is really doing, but there's a significant johnlock scene at the end.