The magnificently mustached local columnist Jim Qwilleran (along with his two Siamese cats, Koko and Yum Yum) has his hands full with numerous projects associated with the town's 150th birthday. But when an aspiring young architect visiting from California -- the nephew (and only heir) of the deceased socialites Nathan and Doris Ledfield -- asks to sketch his renowned home (a renovated apple barn), Qwill happily obliges. When the young man stops by, however, Koko inexplicably assaults the visitor by dropping onto him from an upper balcony. Quill realizes that his extraordinarily perceptive Siamese knows that something unseemly involving the architect is in the works -- but what?