Lee Aaron Rosen

When Reese and Finch discover that their latest POI has connections to Cold War Soviet espionage circles, they quickly learn how covert ops were handled in a world before The Machine. Alan Dale (Lost) guest stars as the person they're tracking.

Sherlock and Joan search for a murderer who used poisonous mushrooms to kill a botany professor and a group of the instructor's students. Also, when Joan is disturbed by loud noise next door, she discovers her neighbor, Trent (Richard Kind), is renting out his home through a vacation site that caters to hard pratiers.

Frank contends with a potentially dirty cop within his ranks when Danny and Baez's investigation into a brutal assault on an NYPD detective reveals the officer may be corrupt. Also, Eddie and Badillo track down the culprits behind the theft of valuable rare works from a celebrated bookstore; Jamie begrudgingly joins Henry as he looks into an old friend's death he deems suspicious; and Erin snoops into the background of a new woman in Anthony's life.

After a teen girl dies from fentanyl-laced pills, a vigilante goes on a killing spree and McCall becomes a suspect.

Alicia prepares for a key interview which could impact the outcome of the race for State's Attorney. Also, Louis Canning pressures Florrick/Agos/Lockhart to agree on a settlement in his wrongful eviction case against the firm.