"Happy Holidays 2015! It has been a rough year for the Quinns, but I would like to start by saying thank you for all of the well wishes and positive missives sent our way." Another Christmas on Nantucket finds Winter Street Inn owner Kelley Quinn reflecting on the past year as he writes a holiday letter to friends and family. Though the year has had its share of misfortune and worry, the Quinns have much to celebrate. Kelley, now single, at least is on better terms with his first wife Margaret, who is using her celebrity to lure customers to the inn in record numbers. Their son Kevin has a beautiful new baby, Genevieve, with the Inn's French housekeeper, Isabelle; and their daughter, Ava, is finally dating a nice guy—her devoted colleague, Scott. Now the Quinns are looking forward to celebrating Genevieve's baptism, welcoming Isabelle to the family, and enjoying the cheer of Nantucket's traditional Christmas Stroll. But just when a peaceful family gathering seems within reach, Kelley's estranged second wife, Mitzi, shows up on the island after souring on her relationship with the inn's former Santa Claus. Soon Kelley isn't the only Quinn entertaining a surprise guest from Christmases past as lovers old and new gather beneath the mistletoe. With jealousy, passion, and eggnog consumption at an all-time high, it's going to take a whole lot more than a Christmas miracle to get the Quinns—and the inn—through the holidays intact.