Lestrade is still living in the Brownstone, getting on everyone's nerves. Particularly Watson's, because she has strong opinions on whether someone who's sneaking off to get drunk every night should be allowed to share living space with a recovering addict. Lestrade is unable to move out and get on with his life because he's convinced he can't be a real detective without Sherlock Holmes holding his hand. So Watson convinces him to try working on the case of finding out who mugged him last night.
The main case starts with a man named Gordon Cushing receiving a box with two ears in it. According to him, they belong to his wife Sarah, who vanished three years ago. When that happened, everyone -- including the police -- assumed he killed her. And he doesn't even want her back, but he would like some evidence of her continued existence so people will stop calling him a murderer. The police confirm that the ears match his wife's DNA, so they set up a ransom drop.
The drop goes poorly, mostly because after Gordon gives his duffel bag full of cash to a mysterious man, he chases the man into the subway tunnels and kills him with a length of rebar. Holmes deduces that the man was a recovering addict, so he and Watson go to the recovery meetings he might have been attending. They run into Sarah, who's supposed to have been missing for three years. She claims that the man who demanded the ransom had recognized her and was blackmailing her before asking for ransom from Gordon.
But what about those ears? Sarah thinks the police might have been comparing the DNA to hair that came from one of Gordon's other women. Gordon admits that there might have been hair from an escort named Kendra, but she turns out to have died years ago. Finally, Holmes realizes that Sarah's plastic surgeon husband must have grown ears on her back so they could be sent in a box. So Sarah was trying to extort ransom for her own theoretical kidnapping.
And Lestrade tracks down the man who mugged him. He thinks he was set up by Holmes, who was spoon-feeding him the clues. Holmes doesn't deny it to Lestrade, but it seems like he actually didn't do it. Lestrade solved the case on his own. So good for him, right? Anyway, he's moving out, which is what's important.
Holmes is practicing the fine art of disarming a bomb. Well, I assume it's a bomb. It's got a countdown in big red numbers. Naturally, he's interrupted by Lestrade shouting about Sherlock's rooster being in his way. This allows Watson and Holmes to exposit that Lestrade's been living at the Brownstone for nineteen days. And Holmes explains that this bomb was made by a demolitions expert who sends Holmes things from time to time. He doesn't know what will happen if he fails, since he's never failed before. He clips a wire and the countdown speeds up.
Watson goes to deal with Lestrade in the video room. Apparently Romulus the Rooster won't let him at the remote, so Watson has to distract the chicken. As Lestrade turns on the football, he thanks Watson for being nice and she gently reminds him that he needs to make a decision about where to go. He has an offer from São Paulo, but he doesn't speak Portuguese. He calls Sherlock "the old cock-handler" as he tries to get her to take one of his job offers.
Now, a guy in a cab. He tells the driver, "I'm him. The guy you've seen on the news. I'm Gordon Cushing." The cabbie asks if he did it, but Gordon gets out without answering.
There's a package next to Gordon's front door. He takes it inside and opens it with a letter opener while drinking some wine. And then he drops the glass because there are ears in the box. Two of them. That makes this episode a spin on "The Adventure of the Cardboard Box," which I've always thought was one of the least exciting story names ever. Calvin and Hobbes have adventures with a cardboard box; Sherlock Holmes should be aiming higher. The Arthur Conan Doyle story features Sherlock telling Lestrade to take all the credit for the case, which is something that the Sherlock of Elementary now regrets doing. It's thematic!
At the police station, Holmes learns the details of Gordon's situation. His wife, Sarah, disappeared in May 2010 and everyone thought he did it. Holmes's excuse for not knowing about this was that he was lost in his addiction at the time. A lot of these cases involve things happening in that window where Holmes wasn't keeping track of crimes, don't they? Anyway, Sarah disappeared and everyone assumed Gordon killed her. But there was no body, so it was hard to get a really good case against him. The box he received just now had a ransom demand and a note saying it contained his wife's ears. And this isn't the first ransom demand he's received; he got another one after she disappeared in June 2011. That time, Gordon followed the instructions to leave cash under a tree in Central Park. And when that was done, he contacted the cops and had no proof that any of it happened, so everyone figured he was just making it up to pretend that he hadn't killed her.