The last thing eighteen-year-old Wilhelmina "Willa" MacCarthy wants is to be a nun. It's 1936, and as the only daughter amongst four sons, her Irish–Catholic family is counting on her to take her vows—but Willa's found another calling. Each day she sneaks away to help Doctor Katherine Winston in her medical clinic in San Francisco's Richmond District. Keeping secrets from her family only becomes more complicated when Willa agrees to help the doctor at a field hospital near the new bridge being built over the Golden Gate. Willa thinks she can handle her new chaotic life, but as she draws closer to a dashing young ironworker and risks grow at the bridge, she discovers that hiding from what she truly wants may be her biggest lie of all.