Despite reports that Serbian mob informants Pytor and Catherine Madrczyk died in an airplane crash, Red suspects that no. 101 on the blacklist, genetic scientist Eric Trettel (aka the Alchemist), helped the Madrczyks escape witness protection by creating virtually perfect doubles who were then killed in the crash. After Liz, Meera and Ressler find Pytor hiding in Budapest, Trettel tracks down and kills his wife. Posing as his lawyer, Trettel then talks the FBI into letting him see Pytor alone so he can kill him, too. Meanwhile, as Tom and Liz proceed with their adoption, tensions arise when he suggests she take some time off to be with their new baby.
As Liz tracks down Molly Trettel and their diabetic eight-year-old daughter, Annie, in Virginia, the Alchemist launches a plan to reunite them by seeking out candidates for their genetic doubles. So when Molly and Annie are found murdered, Liz orders a thorough DNA workup that proves the bodies are doubles and that they’ve actually been kidnapped. Meanwhile, Red enlists a group of high-tech whistle-blowers to reassemble shredded classified documents that can identify the FBI mole responsible for the attempt on his life.
When Liz locates Annie’s insulin pump with a GPS tracker, Trettel tries to run, but is trapped in a gas station when his daughter is hit by a stray bullet. But when Trettel offers to turn over the names of the criminals he’s helped escape in exchange for his freedom, Liz is stunned when he’s killed by a police sniper. Finally, after Liz’s long hours at work create even more trouble for her shaky marriage, Red uses the information he’s received to confront the mole – Meera.