A brave woman tries to breed her English bull with western cattle.

Martha Price, an English widow, arrives in Saint Louis in 1884 with her daughter Hilary, 4 milking cows, and Vindicator, a hornless Hereford bull. She hopes to sell the bull for breeding purposes, believing that the crossbreeding process will improve upon the lean longhorn cattle prevalent in the West. Vindicator is sold to cattle baron Alexander Bowen, a widower originally from Scotland, and saddle tramp Sam Burnett is hired to deliver the bull to Bowen's Texas ranch. Burnett is skeptical of Martha's theories and is at first party to a scheme to swindle her, but he soon changes sides. En route to Texas, James, Bowen's son, is injured in an unsuccessful attempt by roughnecks to steal Vindicator. Martha and Hilary also go to Bowen's ranch, and Bowen falls in love with Martha. Hilary and James fall in love while she is nursing him back to health, and they plan to marry. That winter, Vindicator and some of the other cattle are lost on the range. When the bull is found dead and it is not known whether he mated successfully, Martha resigns herself to marrying Bowen. But Sam, converted to Martha's theories and a new man because he has something to believe in, goes on a long search of the range and returns with a Hereford calf. Martha then decides to stay in Texas, marry Sam, and raise Herefords.