In the courtyards of Trinity College, Dublin, in 1978, aspiring actress Maeve meets pottery student Murtagh Moone. As their relationship progresses, marriage and motherhood come in quick succession, but for Maeve, with the joy of children also comes the struggle to hold on to the truest parts of herself. Decades later, on a small Irish island, the Moone family are poised for celebration but instead are struck by tragedy. Each family member must find solace in their own separate way, until one dazzling truth brings them back together. But as the Moone family confront the past, they also journey toward a future that none of them could have predicted. Except perhaps Maeve herself.

Inside the walls of the Dead Letters Depot, letter detectives work to solve mysteries. They study missing zip codes, illegible handwriting, rain-smudged ink, lost address labels, torn packages, forgotten street names --- all the many twists of fate behind missed birthdays, broken hearts, unheard confessions, pointless accusations, unpaid bills, unanswered prayers. Their mission is to unite lost mail with its intended recipients. But when letters arrive addressed simply to “My Great Love,” longtime letter detective William Woolf faces his greatest mystery to date. Written by a woman to the soulmate she hasn’t met yet, the missives capture William’s heart in ways he didn’t know possible.