Joan returns to 221B and throws herself into the work. Sherlock sees how sad she is but he doesn't say anything, knowing that the best thing to do for her is to proceed with the case. They've been after this murderer for most of the week, so there's a lot of staring at evidence and trying to see something in it that they haven't seen before. It's midnight when Joan suddenly realizes one of the CCTV images had been altered, which led them to question why and who would have the power to do that, which led to them following the trail back to a uniformed officer in the evidence department at the Yard, who had a secret relationship with the victim and killed them to cover it up.

It's four AM when Joan returns from the police station. She goes to 221A, and she sees Ted's coat isn't on the rack. He's not there.

She goes into the bedroom, crawls into bed alone, and holds his pillow, as tears silently slip down her cheeks.

Late the next morning, she gets a devastating phone call.

Ted's phone buzzes around noon. It's Sherlock.