After Jane's (Jaimie Alexander) tattoo reveals a connection between a Korean import/export company and a stolen cache of deadly chemical weapons, the team must race against the clock to stop their release in the New York Stock Exchange. The hunt leads to several tense shootouts, including a poisonous gas scare in which Weller (Sullivan Stapleton) sacrifices his antidote to save Jane. Luckily, Jane is able to save his life in return.
Meanwhile, Patterson (Ashley Johnson) gets a call from a restaurant confirming a dinner reservation placed by David a month prior, for their anniversary. On Borden's (Ukweli Roach) advice, she decides to show up, and she brings along David's last published crossword puzzle. While solving the puzzle, she discovers a hidden message, suggesting David solved another one of Jane's tattoo conundrums before he died.
Patterson isn't the only team member dealing with personal struggles. Following a breakup with Reade (Rob Brown), Sarah (Jordana Spiro) moves out of Weller's apartment. Weller - who's still casually involved with his ex, Allie (Trieste Kelly Dunn) - is even less pleased with Reade than before. Zapata (Audrey Esparza) has fallen back into her most dangerous habit, illegal gambling. And Jane experiences flashbacks of attending her own memorial service a year ago, where she watched her mother and Weller mourn. She also recalls Oscar (Francois Arnaud) accompanying her, and asking, "Are you sure you're still okay with this?"
Later, Jane meets up with Oscar, who tells her that, as the next step in their mission, she needs to seduce Weller and become the person he trusts most. Jane refuses, and Oscar reveals he doesn't want her to, either - he still loves her. Then, in a moment of passion, they both give in to some very strong desires.