Dorinda, a mountain girl, left alone by the death of her parents, is adopted by distant relatives, Mr. and Mrs. Greer. Mrs. Greer is not overjoyed by this addition to their family, because all her mother-love and affection is given to their only son, Harvey, just finishing a term at college.
Billy Garrison, a successful young jockey, rides the favorite "Sis" in the Louisville Derby. He does not ride with his customary vigor and dash. He feels "doped" and entirely out of condition and as a consequence "Sis," instead of winning the race, trails in last under the wire. At the stables he is accused of throwing the race, but denies it.
Billy Garfield is a bright, young railroad engineer. He runs passenger train No. 6, and next to his locomotive, he loves Marie Shaw. They are engaged and their wedding day is set, but Jack Blake, Billy's fireman on the run, and a former suitor for Marie's hand, is jealous and plots to "fix" Billy.