As the longtime local carpool mom, Frances Bloom is sometimes an unwilling witness to her neighbors' private lives. She knows her cousin is hiding her desire for another baby from her spouse, Bill Horton's wife is mysteriously missing, and now this. After the shock of seeing Anne Porter in all her extramarital glory, Frances vows to stay in her own lane. But that's a notion easier said than done when Anne's husband throws her out a couple of days later. The repercussions of the affair reverberate through the four carpool families--and Frances finds herself navigating a moral minefield that could make or break a marriage.