In a small Cape Cod town, Michelle and her mother Fran run a small shop where they sell beach gear, souvenirs, snow globes, and the best fudge around. Michelle's son, Tommy, has just come home from his second stint in rehab, and the financial toll of his heroin addiction has hit the business' bottom line. Meanwhile, a young woman named Lauren is home from college to tend to her ailing mother, and she and Tommy make a connection that changes them both forever. Set over the course of a summer and a winter, Hyannis takes a look at the plague of despair and drugs infecting small town America.