While awaiting word from the mine to see if they found gold, Annie discovers a beloved stagecoach is now being driven by a woman, the daughter of the owner who is now threatening to sell the stage and pocket the money. Annie suspects there's more going on with the mine when they return and announce that there is no gold. Now, she must get to the bottom of things before it's too late for the town.

While Annie and Lofty pursue an outlaw who killed a sheriff, Tagg tries to coach his schoolteacher on the finer points of romance.

A Dutch gunsmith, the inventor of an new rifle with superior range, plans to give the weapon to the United States Army in gratitude for being allowed to immigrate. A crooked businessman decides to take advantage of the man's patriotism and sends an impostor posing as an officer to take possession of the gun before the real colonel can arrive in Diablo.

A retired army officer who has been recalled to active duty in Washington decides to sell his valuable ranch for less than market value just to be rid of the property. He places advertisements in every major newspaper west of the Mississippi seeking buyers. His advertisement not only attracts men interested in real estate, but outlaws who are interested in the large sums of cash the buyers are carrying.

After years of fruitless prospecting, old Scissorbill Childers finally strikes it rich and decides to use his new-found wealth to open a bank to grubstake other prospectors who are searching for gold and silver. New found wealth always attracts criminals so Lofty has his hands full trying to thwart claim-jumpers and swindlers. To make matters worse, the government assayer determines that Childers' gold ore comes from the same claim as that of a murdered prospector.

Annie, Lofty and Tagg try to help a young Indian when he inherits a stagecoach line with a valuable mail contract after his white patron, the owner of company is bushwhacked and murdered. A rival businessman who craves the contract tries to frame the young brave so he can take over the valuable concession.

While riding in the desert, Annie and Tagg meet Tim Lafferty, a strange old Irishman who claims to be searching for treasure with the help of leprechauns who followed him to America from the Auld Country. When a neighbor tries to gain possession of the Biddle family ranch by killing Eliza's brother, Tim proves invaluable to Annie and Lofty by helping them smoke out the killers.

During a heated election campaign between honest lawyer Dave Morgan and Carter Holmes, a crooked politician, the contest takes a violent turn when Holmes tries to have his competitor murdered. When his henchmen fail, Holmes hires a notorious gunfighter to take care of the job, but is surprised when the gunman promises to get Holmes to back out of the election without violence.

Annie and Lofty jail Dobie but he proclaims his innocence while they look for the rest of the gang. Dobie escapes but he and Tagg get kidnapped by the actual culprits, leading Annie to take desperate measures to rescue her brother.

When a girl is blinded in the murder of her father, Annie tries to help her identify the killer.

When orphaned teen Bucky starts hanging out with local tough Mace, a concerned Annie warns his brother Steve. But Bucky defies Steve joining with Mace in a robbery, causing Annie and Lofty to head after them.

Clell Morgan is a former delinquent who is starting over with the help of the Junior Pioneer Club of Diablo. He begins to worry that all that may fall apart when he learns his older brother has escaped from jail and is headed to Diablo.

Two outlaws rob a stage, kill the driver and leave the shotgun guard for dead. The guard survives the attack and, with the help of a passerby, manages to make it to Diablo. The man can't defend himself from charges of robbery and murder because the bullet wound has caused complete amnesia. Annie and Lofty set out to prove the man's innocence.

A tenderfoot from Mississippi travels to Diablo to visit his sister and loses his watch in a stagecoach robbery. The headstrong youth is soon telling everyone how to do their jobs - including questioning Lofty's search for the outlaws who robbed him and his sister's experienced ranch foreman about his business methods. The young man really bites off more than he can chew when he discovers the identity of the thieves and tries to bring in the entire outlaw gang single-handed.

While rummaging through an old trunk, Tagg and his friend Johnny Ward, the son of a murdered lawman, find evidence that they believe proves his uncle is an ex-convict and may be part of the outlaw gang who recently robbed Diablo's bank.

When their handicrafts meant to trade for goods at the local trading post are stolen by white men, the Navajo tribe decides to seek vengeance by going on the warpath. Since whites are forbidden to enter the reservation, even to seek peace, Annie must dress as an Indian maiden to prevent bloodshed.