Phoebe Titus (Jean Arthur) is a tough-as-nails pioneer with dreams of starting a freight service in Tuscon, Ariz. Peter Muncie (William Holden), a vagabond passing through Arizona en route to California, takes a romantic interest in Phoebe and coaxes out her softer side. Just as their romance begins to blossom, Peter packs up and moves on. Though charming southerner Jefferson Carteret (Warren William) steps in to lend a hand, he may be plotting in secret to sabotage Phoebe's nascent business.