When seamstresses Iris and Lily Dickinson are accidental witnesses to a murder, the spinster sisters resolve to keep themselves - and their pristine reputations - a discreet distance away from the sordid business. But the unexpected discovery that the killer might be in their very midst soon changes everything, sparking an urgent desperation to ferret out his identity. While assisting the local constable in his investigation, Iris stumbles across a family mystery of her own, a buried secret that calls into question everything she thinks she knows about her sister. With Iris's once-blind faith in Lily shaken, can the sisters unite long enough to escape the schemes of a dangerous lunatic?