The Perfect Couple follows Amelia Sacks, a bride marrying into one of Nantucket's wealthiest families. The groom's mother Greer Garrison Winbury, a famous novelist, spares no expense on the high-society wedding. But, when a dead body appears on the beach, everyone's Champagne dreams quickly vanish and are replaced by suspicion. As secrets bubble up to the surface, an investigation takes hold that feels plucked from one of Greer's books.