Pun Bandhu

When a famous cancer researcher is found dead, Holmes and Watson must determine if the scientist's untimely demise was tied to his latest cutting-edge invention. Meanwhile, Bell is finally cleared to re-enter the field.

Danny contemplates retiring until Erin enlists him to help her with a case involving her ex-husband, Jack (Peter Hermann). Also, Jamie and Eddie go undercover as a couple, and Frank butts heads with the new mayor of New York City, Margaret Dutton (Lorraine Bracco).

Erin must convince Frank to back a new state police bill as part of a bargain she made with Governor Mendez (David Zayas). Also, Danny and Baez pursue the same perp twice after the DA's office is unconvinced by their initial lineup, and Frank faces a challenge when a cop killer comes up for parole.

Alicia and Diane agree to let a famous liberal lawyer (Jeremy Breslow) aid them on their latest case, but they soon realize he may not have their client's best interests in mind. Meanwhile, Alicia's mother (Stockard Channing) arrives for Thanksgiving seeking moral and legal support from Alicia and her brother Owen. Brian Dennehy returns as Lawyer Bucky Stabler and Bebe Neuwirth returns as Judge Friend.

A severed hand and foot are found in an alley; Megan allows Lacey to film her at work for a school project.