When twenty-something New Yorker Rebecca Strand learns (her father's deathbed confession) that she has a twenty-six-year-old half-sister she never knew existed, she can't wait to meet her. With her lawyer boyfriend's protests ringing in her ears ("She's just going to want her share of his million-dollar estate!"), Rebecca drives to a small coastal town in Maine with the 26 letters her father wrote to Joy every year on her birthday. All alone in the world, Rebecca knocks on Joy Jayhawk's door, having no idea what to expect.

Turns out Joy, the separated mother of a little boy (Rebecca has a nephew!), isn't very interested in the "father" who turned his back on her existence from day one–or her "sister." But Rebecca is so determined to establish family bonds with Joy that she doesn't go home... and finds herself being welcomed into small life by some very loveable, quirky characters, including a sexy carpenter named Theo...