The team goes undercover to pursue the Alchemist, who uses science to transform DNA and who's been assigned to protect a mob informant. Elsewhere, Liz targets an unlikely couple; Tom and Liz's relationship is tested; and Ressler faces a big decision.

Liz helps Tom come to terms about their impending adoption while Red reveals that a woman from his past, Madeline Pratt is the next target on the Blacklist. Elsewhere, at an elaborate party at the Syrian Embassy, Red convinces Liz to pull off a covert heist.