The long-running crime drama continues its 14th series. In this week’s episode, the investigation into the murder of a district attorney takes a sudden twist when police learn that the man was an impostor. The case is then connected to a mob hit ten years earlier.

New York City is stunned by the slaying of ADA Daniel Tenofsky in Central Park. With the mayor (Michael Bloomberg, appearing as himself) taking a personal interest in the case, detectives Briscoe and Green are under pressure to find the killer.

The cops learn that Tenofsky, a highly respected appeals lawyer, was seemingly lured out of his apartment at night by a phone call traced to a local pizza parlour. Briscoe and Green have no idea who placed the call and find few clues at Tenofsky’s apartment. The enigmatic lawyer – dubbed “the nowhere man” by Briscoe – seemingly lived for his work, with no known friends or family. “The more we learn about Tenofsky, the less we know,” Briscoe says.

The case is then turned on its head when Green finds evidence that Tenofsky was living in Arizona when he should have been studying at Brooklyn law school over 20 years ago. School records reveal that the real Daniel Tenofsky dropped out after his first year and is now working at a shipyard. “Who’d wanna impersonate me?” he asks the detectives. The police soon learn that the Tenofsky who worked in the DA’s office was one Jacob Dieter, a bright college graduate from Arizona who never even attended law school.

No one is more stunned by the news than McCoy, who worked alongside Tenofsky for years. McCoy is adamant that, despite his fraudulent identity, Tenofsky was a top-class lawyer – but the appeal court judge wants to re-examine a number of his cases to ensure they were properly handled. McCoy and Southerlyn trawl through Tenofsky’s files and find nothing out of place until they come to the case of a journalist named Robert Parenti.

Parenti went missing ten years ago and Tenofsky tried to indict notorious mafia boss Franco Tortomassi for his murder. Tenofsky’s case relied upon the testimony of two of Tortomassi’s lieutenants – nicknamed ‘Biscuits’ and ‘Books’ (Steve Schirripa, ‘The Sopranos’) who were willing to testify against their boss in return for immunity. The open-and-shut case was abandoned abruptly and most of the paperwork has been lost – raising the possibility that Tenofsky was threatened or bribed to drop the charges.

Briscoe and Green re-open the Parenti case and soon find a mountain of evidence suggesting Biscuits and Books killed Parenti. The journalist’s own wife says her husband knew his life was in danger. “He said, ‘if anything happens to me, tell them Biscuits and Books done it’,” she says. Briscoe is also able to tie the two gangsters to Tenofsky’s murder when he discovers that Biscuit’s uncle used to own the pizza parlour where the phone call to Tenofsky originated.

McCoy has enough evidence to have Biscuits and Books arrested – but their smooth lawyer argues that the pair still have the immunity from prosecution granted them by Tenofsky. McCoy overcomes this obstacle by pointing out that proof of their immunity has been lost from the file.

However, there is another problem – Parenti’s body was never found. A brilliant insight by McCoy leads to its discovery at a building site and, in the face of this damning new evidence, Biscuits and Books are suddenly keen to confess. “They can give you the man who ordered Parenti and Tenofsky’s murders,” their lawyer tells McCoy. The prosecutor now has Franco Tortomassi in his sights – but can he explain why the mob boss wanted Tenofsky and Parenti dead? And can he clear his colleague Tenofsky of any wrongdoing?