Three weeks later, Elizabeth Zott and Calvin Evans leave work arguing about protein synthesis, their debate exposing simmering tension. Both have met several times, each trying to keep things strictly professional despite strong attraction. The result is frustration: brief meetings that become the high point of their days, followed by deflated departures.

At her car, Elizabeth references recent silkworm research—bombykol, a female pheromone—as a coded signal of attraction. Calvin, insecure about past missteps and determined to appear detached, responds flippantly about “worms,” which Elizabeth reads as disinterest. She prepares to leave, convinced he has no romantic interest and suspects she only wants lab equipment.

They trade curt goodbyes—Calvin asks about weekend plans; Elizabeth lies, he snaps, and walks off. Alone, Elizabeth realizes she is falling in love, while Calvin, equally conflicted, rethinks the exchange and returns to her car window.

After a brief, sharp exchange—Elizabeth denies angling for equipment; Calvin insists he isn’t the problem—Elizabeth acts on her feelings, pulling him into a kiss. The moment resolves their miscommunication and marks a decisive shift from professional partnership to a romantic bond.