Travis Yancey, newly installed U.S. Marshal, has been asked by President Andrew Johnson to take on a special assignment. One of the president's friends and campaign contributors, Henry Waring, has recently died under suspicious circumstances, and Travis is called upon to investigate what might be a murder. Working under presidential authority, Travis hires a crew to accompany him on this mission to Rancho Riata, near San Juan Capistrano in Southern California. Martha Waring, second wife and now the widow of Henry, and her two stepdaughters, Rosamond and Olivia, welcome the posse to their ranch. However, Henry's lawyer, Richard Hotchkiss, is not so welcoming. In fact, by the next morning, when Travis is ready to begin his inquiries, the lawyer has inexplicably decamped, along with Henry's secretary and his ranch manager. The hunt is on, to find not only these three Waring employees but also the mysterious "Chief", who exists somewhere in the background and may have been involved in Henry Waring's death. Travis is aided in the investigation by his own posse and by Rosamond Waring, a spunky sassy girl wearing wire-framed spectacles. Travis, confirmed bachelor and vehement opponent of marriage, finds himself falling hard for Rose. All the more so when, on her own, she deliberately enters the lion's den, leaving him torn between apprehending a gang of desperadoes and rescuing the woman he loves.