When a priest confesses to the murder of a parishioner, everyone in the wealthy waterfront town of Pequot Bays is convinced of his guilt-everyone, that is, except Marya Cook, a Bible-quoting, lavender-clad octogenarian known to locals as the Purple Pest.

Unable to prove his innocence on her own, she draws in Martha Collins, a much younger, efficient, ever-busy church lady, to assist in her investigations. Although Martha is unwilling to associate herself with the odd old woman as she accuses wealthy and influential suspects of murder, Marya's peculiar logic persuades her that this ditzy old woman may not be so ditzy after all.

A victim with plenty of enemies, a corrupt ambitious cop, a conflicting confession by a fellow priest, and the death of a prime suspect make the path to truth a crooked one. The rich and powerful suspects scoff at poor, dithering Marya. Can she, in the end, unveil their many secrets and prove there is more to a person than meets the eye?