Montana Sky by Nora Roberts - Romance>Suspense/Mystery/Thriller
When Jack Mercy died, he left behind a ranch worth nearly twenty million dollars. Now his three daughters—each born of a different marriage, and each unknown by the others—are gathered to hear the reading of the will. But the women are shocked to learn that before any of them can inherit, they must live together on the ranch for one year. They are sisters—and strangers. Now they face a challenge: to put their bitterness aside and live like family. To protect each other from danger—and unite against an enemy who threatens to destroy them all?