In 1869, Gloriana Womack's family is much smaller since smallpox killed her mother and two of her siblings. She lives in a modest cottage in Duluth, Minnesota, with her father and young brother, and she has dedicated her life to holding her tiny, fractured family together - especially as her father is frequently gone on long fishing trips. Their livelihood may come from the waters of Lake Superior, but storms on the lake can be dangerous, even to those who know it well. Luke Carson has come to Duluth to help shepherd the arrival of the railroad to the city's port.

Living in London's poorest slum, Mercy Wilkins has little hope of a better life. When she's offered an opportunity to join a bride ship sailing to British Columbia, she agrees. After witnessing so much painful heartache and loss in the slums, the bride ship is her only prospect to escape a bleak future, not only for herself but, she hopes, someday for her sister. Wealthy and titled Joseph Colville leaves home and takes to the sea - as ship's surgeon - in order to escape the pain of losing his family. When Mercy becomes his assistant, the two must fight against a forbidden love. 

Faith Kenner is pursuing her dream to become a doctor at Willamette University's medical college so she can use her gift for healing to help those in need, especially the native populations forced onto reservations and then neglected. When she meets Andrew Gratton, a handsome riverboat captain who has been injured on his ship, she uses her skills to tend his wound, and a friendship grows between them. But Faith holds a secret that means their friendship can never become anything more, so she must bury her feelings for Andrew as best she can. 

Portland, Oregon, 1879. Nancy Pritchard finds herself a widow with a world of problems when her deceased husband's schemes start to come to light. As she searches through the pieces of her loveless marriage, Nancy realizes there is a lot that she didn't know about this man. Seth Carpenter is a childhood friend of Nancy's who has recently returned to Portland. He's delighted to see her again, and as a lawyer, he is able to help her sort through the legal aspects of her husband's death. 

Jeffery O'Donnell is captivated by the mysterious Simone, who arrives at his office hoping to acquire a position as a Harvey Girl at the popular way-stops along the frontier rail line. Jeffery is torn, however, when he suspects that Simone may harbor a disturbing secret.