She's a Pinkerton detective. He's working undercover for Wells Fargo. Neither has a clue about love.

Annie Beckman arrives at Last Chance Ranch in the Arizona Territory holding the classified ad she found. Miss Walker's search for an heiress who is single and willing to remain so gives her the perfect cover. As a detective for the Pinkerton Agency, Annie's latest clandestine task is to discover the identity of the mysterious Phantom, a train robber thought to be hiding out at the ranch.

Ranch hand and undercover Wells Fargo detective Jeremy Taggert is secretly tracking the Phantom too, but Annie suspects he may be the train robber she's after. They're constantly at odds and she even goes so far as to serve him gunpowder tea in an attempt to gain the upper hand.

Danger lurks around every corner and everyone is under suspicion - even Miss Walker! It'll be a race to the finish to see which rival detective finds the Phantom first. Nothing - not even romance - can get in their way.