Just after making a large gold discovery, an old prospector is ambushed and killed by three masked men but manages to kill two of his attackers before he dies. He also manages to scribble out a will, which is given to detective "Silver" Ward Hogan, who is hired to track down the legitimate heirs and to try to find the third murderer.

Just before Christmas in the town of Millard, gold prospector Ben Merriweather is shot by three bandits. Ben manages to kill two of his assailents, Roy and Pete Ryerson, and write a will leaving his considerable fortune in gold to David Kingman, Clinton Gunston, Henry Devers and John Briggs. He then sees the third bandit, and as he lays dying, indicates to a friend that the third bandit is one of the men in the will. Soon after, lawyer Damion Bard sends for famed Western detective Silver Ward Hogan to investigate Ben's murder and verify the legality of the heirs. Ward will earn $50,000 if he succeeds, but the only leads Damion can give him are the will, which includes an unfinished sentence mentioning "Judas," and the knowledge that the Ryersons' brother Jess is still alive. With Ben's mule in tow, Ward sets out to find Briggs, and along the way apprehends a young man following him, who introduces himself as Johnny B. and explains that he is competing with Ward for the reward money. Ward turns down Johnny's offer to become partners, but invites him to ride with him to Briggs's store. There, Briggs explains that he has never met Ben, and by the time Ward leaves Briggs's office, Johnny has disappeared. Ward travels on to David Kingman's ranch, where he stops to bathe in a lake. As he bathes, widowed ranch owner Mary Kingman, fearing that Ward is an intruder, holds him at gunpoint, until her father Job recognizes Ward and invites him to dinner. There, Ward learns that David is Mary's young son, whom Ben met weeks earlier admiring a pair of red boots in a store window. Ward gently discourages David's materialism, and later asks Mary to walk with him in the moonlight, but she pointedly informs him that he would find the walk too chilly. Hours later, however, the two share a midnight snack, and although Ward is attracted to Mary, he explains that he does not want to settle down. In the morning, Ward leaves a silver bullet for David and heads on to Gunston's town. There, Sheriff Crowley leads him to Gunston's humble, dusty ranch, on which the former outlaw is trying, for the sake of his young wife Sally, to eke out an honest living. Assuming Ward believes he killed Ben, Gunston explains that he and Ben were prison cellmates years earlier and have not spoken since. After Ward leaves, Gunston, who fears that the dusty ranch is exacerbating Sally's asthma, wonders if he should turn back to crime. Even though Sally vows to leave him, in desperation he robs that night's mail stage. In the morning, Crowley invites Ward along to arrest Gunston, and at the ranch, they watch as Gunston returns from his raid to inform Sally that he has found the inheritance notice letter from Damion in the stage's mailbag. Realizing that he came back only to give her the money, she promises to wait for him until he completes his jail term. Confused about Ben's motives for choosing his heirs, Ward returns to Millard, where he is pleased to run into Mary and David. Johnny is with them, and to discourage the younger man's attentions to Mary, Ward offers to drive her to the ranch she is considering buying for David with his inheritance. They flirt, but once back in town, Ward inadvertently offends Mary by suggesting that she is encouraging him to stay in town. Ward leaves again soon after to look for Devers, whom he finds in a deserted town inhabited by a few Indians and rancher Art Birdwell. The rheumatic Devers at first claims that Ben, his ex-partner, stole a gold claim from him, but at Ward's gentle prodding, admits that he stole it from Ben. Later, Art picks up Devers' inheritance letter for him, then convinces the old man to endorse the check so Art can deposit it in the bank for him. When Ward then hears that Art cashed the check and rode off in the opposite direction, he speeds to Devers' house, but there finds Art and Devers playing poker. Art explains that he tried to steal the money, but his conscience stopped him. Next, Ward pays a source to reveal that Jess Ryerson is staying at the local hotel. When Ward tries to arrest him, Jess bitterly reveals that his brothers shot him in the spine years earlier, rendering him paralyzed. Outside, Ward finds Johnny, and invites him to travel back to Millard with him. Along the way, Ward explains that he has guessed Ben's method of choosing heirs: he has decided to give fortunes to men too weak to create their own. That night, Ward hears Johnny call the mule "Judas," and realizing that Johnny must have known Ben, deduces he is the third bandit. He confronts the younger man, who asserts that he was Ben's partner and wanted only his share of the stake, but the Ryersons killed the prospector out of spite. After Johnny fires at Ward to avoid capture, Ward is forced to shoot Johnny in the arm. As Ward is tending the wound, Johnny admits that his real name is John Briggs. To Johnny's surprise, Ward promises to testify that he did not kill Ben. Soon after, Ward visits Mary and declares that he is ready to settle down. Mary responds by asking him to walk in the moonlight, stating that this time there will be no chill.