Edward J. Meagher

A giant condor decimates a herd of sheep, and Rin-Tin-Tin is accused of having turned killer.

At the beginning of the Civil War, as federal troops start to build the first overland telegraph, Indians, who fear the wires, kill some of the linesmen. In response, Major Hammond, who oversees the troops, requests that President Abraham Lincoln send twenty thousand more soldiers to come to his aid. Lincoln grants Hammond's request, and sends along Capt. Allen, who is knowledgeable about Indians. At his new post, Allen discovers that a Confederate spy has been fomenting trouble with the Indians. Allen eventually uncovers the spy, makes peace with the Indians and wins the love of Dorothy, a young woman who lives at the post.

An undercover agent tracks a gang of drug smugglers to their headquarters in Mexico, a nightclub, where he manages to get a job as a bouncer. There he meets and falls for a pretty young woman, whose father happens to be the man the agent suspects of heading the gang.

Joe Ryan, a veteran train engineer, is demoted to a flagman position after a disastrous crash-- one caused by his cowardly and opportunistic partner. Though Ryan's failing eyesight is named as the cause of the crash, he's undeterred as he designs an automatic braking invention.

Bob and Jim Whitely are twin brothers. Bob, an army veteran who suffered shell shock in the war, escapes from a sanitarium and holds up the Express train, for which Jim is mistakenly arrested. Jim soon escapes from jail in order to find his brother. However, his task is complicated by a crooked sheriff who pins a holdup and murder on him that the sheriff himself actually committed. To make matters worse, the murder victim was Tommy Wilkins, the brother of Jim's fiancee, who now thinks that Jim killed her brother.

A soldier returns home from World War I with a beautiful black horse that he saved on the battlefield, and names Thunderhoof. He enters the horse in a local race, hoping to earn enough money to save the family ranch of the girl he loves. However, the crooks intent on taking the ranch manage to capture a notorious wild horse and enter it in the same race, believing that it can beat Thunderhoof and thereby ensure that they're able to take the ranch.

An underworld story about a boy (Charles Delaney) suspected of being a stool pigeon but in reality, he is only stealing to give his mother a better life. His devoted girlfriend Goldie (Olive Borden) tries to help him turn his life around.

Klondike the German Shepherd dog works with the Northwest Canadian Mounted Police to track down smugglers.

When Rin-Tin-Tin's master is found murdered, Rinty is accused of the crime.