The FBI is on the hunt for a high-ranking Chinese spy, Wujing which Red claims has hired him to help decode a classified CIA transmission. Liz, posing as an FBI cryptographer goes with Red to decode the message while protecting US government secrets. Meanwhile, Liz proactively investigates Tom.

Red informs the team that "The Alchemist" - a man who relies upon science to transform a person’s DNA - has been contracted to protect a well-known mob informant and his wife. As the team goes undercover to catch him, Liz finds herself on the hunt for an unlikely couple. Meanwhile Liz and Tom find themselves at another bump in their relationship and Ressler debates whether or not he should give his ex-girlfriend his blessing.