The next morning, Watson disassembles a dinosaur that Holmes had apparently constructed. She also has the correct molecule, because she emailed her old genetics prof. It's a man-made chemical, which is a mutagen. The next question is whether they prove that someone paid a genius to create it. Holmes stands weirdly and gets Watson to go pick up his dry cleaning. Swerve!

At the cleaners, Watson is ignored by the woman behind the counter, who speaks a foreign language and is watching television. Everything she says is translated into English by a bald guy wearing sunglasses. Watson notes a fur coat, then gets a text to meet at the police station. The woman claims the bill is $75, then drops it to $19. Watson asks for a receipt, but one is not forthcoming. That was odd,

At the police station, Benny is being interrogated by Gregson and Bell. He's mad about being called an incurable sociopath in Kademan's original paper. Also he denies killing her. From behind the interrogation mirror, Holmes says Benny is a blackmailer and a blackguard, but he's innocent. Bell tells Benny that they have his DNA on file since he's a felon. Then he and Gregson get texts saying "Sociopath but not killer" and "Innocent!" Then Holmes bangs on the mirror when they won't stop interrogating him. He insists that this crime is too elegant for this guy to do it. Bell still wants to run the DNA and Gregson mocks Holmes's theory. Holmes is off to prove the validity his crazy ideas.

A Lydon son thinks Holmes is wacky. He's also not sure he can give them access to the servers. Another Lydon walks in to report that Gerald Lydon (their father) was declared incompetent earlier today. So, he concludes, "Get out!" Watson makes up some nonsense about how they can't be fired without something in writing. Outside, Watson gloats that Carter chews his nails, and maybe he chews his pen, which she kept. But Holmes stole his comb. And he's carrying an evidence bag, which he recommends Watson start doing as well. The point is that they now have his DNA. Bell calls in. Benny Cordero's blood came back as a match. They're booking him for murder.

Benny swears it's not his blood. Bell gloats that they test a number of genetic markers. This is a bit of a giveaway, since this episode is all about DNA twiddling. Then Benny comes out with his alibi. He saw a husband and nanny across from his place. He was taking blackmail pictures with a zoom lens. Well, it's worth checking out, right?