In the close-knit community of Chesapeake Shores, Maryland, Susie O'Brien and Mack Franklin's 'not dating' claim befuddles everyone, especially since the two spend every spare minute together. Susie's thrilled when their friendship finally heats up. Then, just when happily-ever-after seems within reach, Mack loses the job he loves and Susie faces a devastating diagnosis. But O'Briens always unite in a crisis.