This week on Elementary, Joan and Sherlock investigate the murder of two men who were trying to solve a complicated mathematical problem.

Elementary season 2, episode 2, “Solve for X” begins with a man being mugged. The mugger then runs off and hears someone being shot. He is then seen by the murderer, and is shot.

Sherlock arrives at the scene of the murder of Felix Soto and chats with Detective Bell. The two search the house and discover a mathematical proof on the wall of one room, only seen with blacklight. The mugger is still alive, but is not awake yet.

Meanwhile, Joan visited the grave of her patient, Mr. Castoro, whose death ultimately led to her quitting her job. She meets his son Joey there and the two talk go for coffee. He asks her to be an investor in the bar he wants to purchase with a partner.

An acquaintance of Sherlock’s looks at the formula and discovers it’s part of a proof for P versus NP, a complex mathematical computer science problem. The correct finished formula is worth a million dollars as it's one of the Millennium Prize Problems. They deduce Soto and another man wrote the formula.

Joan tells Sherlock she wants an advancement on her salary, so she can give Joey money for the bar. Sherlock thinks Joey is just using her guilt over his father to take advantage of her, as this is not the first time he’s asked for cash. Joan tells Sherlock Joey’s mother sued her after his father died because of a mistake she made during surgery. Joey wrote a letter to her saying he didn’t blame her, and it meant a lot to her.

They visit professor Tanya Barrett who had met Soto before and is interested in P versus NP to see if she had any information. Sherlock sees the other man’s writing in one of her books and that leads them to suspect mathematician Cyril Mauer killed his partner to take all the credit. The case is not that simple as Detective Bell calls and says Mauer is dead. He was killed the same night as Soto, and the house was bugged, along with cameras aimed at the house.

They visit Mr. Roe from the security firm that made the camera and he says they were spying on the mathematicians. If P versus MP was solved, it could be a way to hack into anything. He says they hired Barrett as a consultant, and she said the two men were not able to solve the formula.

The police bring Barrett in for questioning. She claims she lied to Roe because she didn’t want him to know Soto and Mauer were close to solving the formula. She took the consultation because she needed money. She admits to having a dog, the very kind that matches dog hair found at the crime scene. She also had the same gun used to shoot both men, but says it was stolen a month ago and she filed a report. She has evidence stacked against her, but provides a solid alibi. She was having dinner and drinks her friend Dean Kaneshiro at the time.

They receive surveillance tape for the restaurant and see her alibi is true. They then look into her ex-boyfriend because she claims he was threatening her through emails. He denies everything when questioned. The mugger woke up and describes Barrett as his shooter.

Sherlock and Joan reexamine the tape and Joan notes the beer is really cheap. They realize beer would only be that cheap during happy hour, and figure out the digital time stamp was changed. They confront Barrett and reveal Kaneshiro admitted to helping her. She had already solved P versus MP and wanted to use it to steal money and so she killed Soto and Mauer before they could finish their formula.

Sherlock agrees to give Joan the money, though he thinks it’s a bad idea. He gives her $20,000 and says to give it to Joey so he will get out of her life. She decides to do something different. She tells Joey she will always support his ventures, but will only give him the money if it’s to go back to college, like his father wanted. She returns home and says Joey didn’t make a decision yet. The episode ends on a touching note, with Sherlock asking if he could visit Castoro’s grave with her next time, and Joan saying yes.

Comments:

For me, this was another wonderful episode of Elementary. I think the murderer was easy to guess, but the math part was different and entertaining. The best part of this week (and every week really) was the interaction between Joan and Sherlock. Joan talked about her mistake and the effect it had on her, and Sherlock showed he cared. Also, we got to see more of Detective Bell this week, which is always great. I loved the scenes between him and Sherlock. For those interested, Clyde (the turtle) is returning for the third episode. I hope Ms. Hudson and Alfredo return this season as well, as they were two of my favorite side characters from last season.

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