Curley Temple loves the daughter of his employer, Jim Harden. Fannie Harden, however, has a mind of her own, and arranges to meet Curley, to talk it over, at the lone tree on the prairie. The ranchman, in looking over his stock, discovers some calves belonging to his herd carrying a brand differing from his own. He accordingly calls the boys together, and offers a reward for the capture of the rustler. The rustler, one of his own cowboys, meets the cattle thieves in the mountains, and obtains branding irons, and the offer of $5 for every calf he brands. He conceals the branding irons in the tree until such time as he can find to do a little rustling. Curley arrives at the tree to keep his tryst, and hearing a bunch of the cowboys approaching, conceals himself to avoid their questions, fearing that they may have seen the letter Fannie placed in his saddle. They arrive at the tree and finding his horse, look around for him, and then spying the branding irons left by the rustler, jump to the conclusion that he is guilty, and start a search for him. Realizing that the boys are apt to be hasty, Curley appropriates the nearest horse at hand, and is in full flight, before the cowboys see him. They mount and give chase. In the meantime, the real rustler, finding the coast clear, comes to the tree and starts building a fire in which to heat his irons. He is thus engaged when Fannie, coming to keep her appointment with Curley, discovers the rustler. Fannie realizes she has discovered the rustler and must find away to let the others know in order to save Curley.