When Alvirah and Willy, two of Clark's most beloved characters, become caught up in a Christmas mystery, all of Alvirah's deductive powers and Willy's world-class common sense are called upon. It begins when an unmarried woman leaves her newborn on the rectory doorstep of a Manhattan church. Meanwhile, a small-time thief and drug peddler is absconding from the church with a treasured artifact, a chalice adorned with a single star-shaped diamond. To elude the police, he grabs the stroller and disappears.
Seven years later, the young mother returns to the church where her child was kidnapped while Alvirah and Willy are helping
neighborhood kids prepare for a Christmas pageant at an after-school shelter. But the future of the shelter is threatened
when the city condemns the site and it is learned that the brownstone to which the shelter was moving has been willed to a smooth-talking couple, tenants in the building. Suspecting that the will is a fake and the tenants con artists, Alvirah sets out to discover the truth. Soon she finds herself in the middle of the puzzle of the missing child and chalice.