Set in early 20th century Chicago, the story centers around Veronica Fisher, a talented and spirited saleswoman, and Andrew Larkin, a determined salesman. Both work at Oberkugen's music shop, owned by the affable but quirky Otto Oberkugen. Despite sharing the workplace, Veronica and Andrew are constantly at odds, finding each other unbearable on a personal level. However, unbeknownst to them, they communicate anonymously through letters as secret pen pals, each developing a deep affection for the other under the pseudonyms Miss Smith and Mr. Box 237.

As the shop navigates its day-to-day challenges, including keeping up with the latest musical trends and handling difficult customers, Veronica and Andrew’s professional rivalry intensifies. They continue their correspondence, both anticipating the day they will meet their mysterious pen pal in person. Their relationship takes unexpected turns as they go head-to-head in sales competitions while simultaneously finding solace in their romantic letters. This dual dynamic of love and animosity propels them toward an eventual revelation that will challenge their perceptions and change their lives forever. The narrative intertwines themes of mistaken identities, transformation, and romantic intrigue, set against a backdrop of charming music and heartfelt comedy.