For three Cape Cod residents, the influx of summer visitors is no more than a minor nuisance--until it brings a man who threatens the balance of their delicate relationship   For more than a decade, Dinah, Susan, and Susan's husband, Willie--artists and neighbors in a small Cape Cod town--have enjoyed an unconventional, but deeply satisfying, three-way relationship. When the annual summer crowd flocks to the Cape, Dinah misses her quiet afternoons composing music in the woods, and Willie, a sculptor, puts aside his own work to do carpentry jobs on lavish vacation homes. Susan, though, envies the glamorous lives of the summer residents. And one visitor, Tyrone Burdock, a wealthy and seductive financier, offers her an enticing glimpse into his world that may jolt the foundation of her ménage à trois.   The clash between moneyed newcomers and the soulful artists who live on the Cape year-round shakes the threesome's external world and the bonds holding them together as they see their bohemian enclave becoming a bourgeois retreat. Bestselling author Marge Piercy skillfully navigates this unique landscape with vivid details and an eye for emotional complexity, bringing these singular characters to life as their relationship undergoes profound changes that will resonate long after the summer people have left.