One summer evening, Lib Hanson is confronted by her painful past when Matt Marlow, the forty-year-old son she abandoned as an infant, shows up on her porch. Fiercely independent, Lib has never revealed her son's existence—or her previous marriage—to her husband, Jack. Married nearly three decades but living in separate houses (to the confusion but acceptance of their neighbors), they enjoy an ease and comfort together in small-town Anthem, Wisconsin. But Jack is a stickler for honesty, and Lib's long-dormant secret threatens to unravel their lives.

When ten-year-old Charlie Taylor arrives at Jack's workshop shortly thereafter, he's not the first kid in town to need help with a flat tire, and Jack gladly makes the repair to his bike. The Taylors are new to Anthem, and Jack soon discovers that Charlie and his mom, Claire, are struggling to fit in, even as Charlie's dad, Dan, is thriving in his new job. Extending friendship and kindness, as well as introductions around the local cafe, Jack assumes a grandfatherly role. What he doesn't see is the drinking that Claire hides from everyone, or the secret son that Lib has allowed to move into her house and the growing attraction between Claire and Matt. When the terrible events of a fateful evening threaten everyone's carefully crafted lives, they must each determine the value of truth for the ones they love.