Joshua and Lauren are the perfect couple. Newly married, they're wildly in love, each on a successful and rewarding career path. Then Lauren is diagnosed with a terminal illness. As Lauren's disease progresses, Joshua struggles to make the most of the time he has left with his wife and to come to terms with his future - a future without the only woman he's ever loved. He's so consumed with finding a way to avoid the inevitable ending that he never imagines his life after Lauren. But Lauren has a plan to keep her husband moving forward. A plan hidden in the letters she leaves him.

Lark Smith has always had a plan for her life: find a fantastic guy, create a marriage as blissful as her parents’, pop out a couple of kids, and build a rewarding career as an oncologist. Things aren’t going so well. For one, the guy didn’t work out. Theoretically, she’d love to find someone else, but it hasn’t happened. Two, she’s just been transferred out of Oncology for being too emotional. (Is it her fault she’s a weeper?) Three, her parents just split up. Deviating from the plan was … well, not in the plan. A potential solution comes from the foul-tempered surgeon Lorenzo Santini.

Hollis Shaw, creator of the popular food blog, Hungry with Hollis, is shocked when her heart surgeon husband, Matthew, is killed in a one-car accident on a snowy morning. The cracks in Hollis’s perfect life—her strained marriage and her complicated relationship with her daughter, Caroline—grow deeper. So when Hollis hears about something called a “Five-Star Weekend”—one woman organizes a trip for her best friend from each phase of her life: her teenage years, her twenties, her thirties, and midlife—she decides to host her own Five-Star Weekend on Nantucket.

Heather is happy . . . ish. She has a successful business, a cute but contemptuous cat, and best friends Daphne and Tori who know where she’s broken and love her anyway. So why does she feel crushed when her ex gets serious about someone new? No problem, she has a plan. More connections will hold her together while her world falls apart, so she finally reaches out to the stranger who might be her dad.

Heather Willette has a good life in Concord, Massachusetts—complete with a husband who runs his own business and a son to take up his mantle one day. But now that her marriage has fizzled out and Ross, her only child, is graduating from college and getting serious with his girlfriend, Heather wonders if that life is the one she really wants. Ready to seek out her own happiness and discover herself again, Heather decides to leave her husband and rent a cottage on Nantucket.