Fresh off a bad breakup with a longtime boyfriend, Nantucket sweetheart Lizbet Keaton is desperately seeking a second act. When she’s named the new general manager of the Hotel Nantucket, a once Gilded Age gem turned abandoned eyesore, she hopes that her local expertise and charismatic staff can win the favor of their new London billionaire owner, Xavier Darling, as well as that of Shelly Carpenter, the wildly popular Instagram tastemaker who can help put them back on the map.

Irene Steele shares her idyllic life in a beautiful Iowa City Victorian house with a husband who loves her to sky-writing, sentimental extremes. But as she rings in the new year one cold and snowy night, everything she thought she knew falls to pieces with a shocking phone call: her beloved husband, away on business, has been killed in a helicopter crash. Before Irene can even process the news, she must first confront the perplexing details of her husband's death on the distant Caribbean island of St. John.

After uprooting her life in the States, Irene Steele has just settled in at the villa on St. John where her husband Russ had been living a double life. But a visit from the FBI shakes her foundations, and Irene once again learns just how little she knew about the man she loved. With help from their friends, Irene and her sons set up their lives while evidence mounts that the helicopter crash that killed Russ may not have been an accident.

On a perfect June day, Vivian Howe, author of 13 beach novels and mother of three nearly grown children, is killed in a hit-and-run car accident while jogging near her home on Nantucket. She ascends to the Beyond where she's assigned to a Person named Martha, who allows Vivi to watch what happens below for one last summer. Vivi also is granted three “nudges” to change the outcome of events on earth.

Adrienne Dealey has spent the past six years working for hotels in exotic resort towns. This summer she has decided to make Nantucket home. Left flat broke by her ex-boyfriend, she is desperate to earn some fast money. When the desirable Thatcher Smith, owner of Nantucket's hottest restaurant, is the only one to offer her a job, she wonders if she can get by with no restaurant experience. Thatcher gives Adrienne a crash course in the business...and they share an instant attraction.

Nantucket is only 11 miles away from Martha's Vineyard. But they may as well be worlds apart for estranged twin sisters Harper and Tabitha Frost. After not speaking for more than a decade, Harper and Tabitha switch islands - and lives - to save what's left of their splintered family. But the twins quickly discover that the secrets, lies, and gossip they thought they'd outrun can travel between islands just as easily as they can. Will Harper and Tabitha be able to bury the hatchet and end their sibling rivalry once and for all?

Single mom Robyn Caldwell needs a new plan for her future. She has always put her family first. Now, with her kids grown, she yearns for a change. But what can she do when her daughter has become the most demanding bride ever, her son won’t even consider college, her best friend is on the brink of marital disaster and her ex is making a monumentally bad decision that could ruin everything?

Hot-shot lawyer McKenna Keaton finds herself in hot water with her own law firm when she’s (falsely!) accused of embezzlement. Placed on unpaid leave, she suddenly finds herself with the free time to return home and attend her youngest sister’s wedding activities. But it’s not all fun and games. Waiting back home is shy, nerdy Henry Blumenthal—McKenna’s high school rival for valedictorian who once took three hours to beat her at chess. Scratch that. He’s Hank Blume now, the famed documentarian, Durham, North Carolina’s, darling son.

Meredith Martin Delinn just lost everything: Her friends, her homes, her social standing - because her husband Freddy cheated rich investors out of billions of dollars. Desperate and facing homelessness, Meredith receives a call from her old best friend, Constance Flute. Connie's had recent worries of her own, and the two depart for a summer on Nantucket in an attempt to heal. But the island can't offer complete escape, and they're plagued by new and old troubles alike.

When CIA Agent Alisa Flynn flaunts the rules by breaking into a mansion in the middle of the night, she skillfully circumvents alarms and outwits guards only to find herself standing in billionaire Gabe Korgan's study...busted by Korgan himself. This could cost her her job unless, in a split second, she can turn the tables and try to convince him to join her on the most important mission of her life. In a ripped-from-the-headlines plot, schoolgirls in Africa have been kidnapped, and Alisa knows that Korgan has the courage, financial means, and high-tech weaponry to help rescue them.

Each of us has a question we dread. When the simple community of Lakehaven is shaken by a violent crime, doubts begin to arise among the locals about whom they can trust.

Joan Blakely had an unconventional childhood: the daughter of a globe-trotting supermodel and a world-famous artist. Her artist father died on 9/11, and Joan—an art historian by training—has spent more than a decade maintaining his legacy. Life in the art world is beginning to wear on her—and then one fateful afternoon her husband drops a bombshell: he’s fathered twins with another woman.

Whitney and Will are a perfect couple by all appearances, their relationship rock-solid and their engagement soon to be announced. Before their impending nuptials, however, Whitney suggests a lighthearted experiment: Why not give each other three romantic "free passes" before getting married? On what's meant to be the last night of a romantic Barcelona vacation, they agree to regale one another with details of these harmless trysts. They grin and bear it and fall asleep feeling mostly satisfied and relieved to be firmly together again. But then a volcano erupts overnight....

Angela's graduate school days at MIT come to an abrupt end when she uses her hacking skills on another student's computer. Yet her mentor, Eve Abajian, arranges a new beginning for her - as an intern in FBI's Boston field office. Her new supervisor, Assistant Special Agent in Charge William Keats, one of only two agents in the Northeast to make his rank before the age of 30, sees in Angela a fellow prodigy. But Angela's skills come with a natural curiosity, which is also a dangerous liability.

Kelley Quinn is the owner of Nantucket's Winter Street Inn and the proud father of four, all of them grown and living in varying states of disarray. Patrick, the eldest, is a hedge fund manager with a guilty conscience. Kevin, a bartender, is secretly sleeping with a French housekeeper named Isabelle. Ava, a school teacher, is finally dating the perfect guy but can't get him to commit. And Bart, the youngest and only child of Kelley's second marriage to Mitzi, has recently shocked everyone by joining the Marines.