At the Mercy of Men

The TARDIS materialises not far from Paris in 1794 — one of the bloodiest years following the French Revolution of 1789. The travellers become involved with an escape chain rescuing prisoners from the guillotine and get caught up in the machinations of an English undercover spy, James Stirling — alias Lemaitre, governor of the Conciergerie prison.

Escaping after an early morning bank robbery, Gentleman Joe and his pal succeed in boarding a freight train headed toward Lone Point. Fearing rightly that a warning has been sent down the line, they secrete their loot in a box car, and, after noting its number, alight and seek cover until after the pursuit has cooled.

Stallings' plot to spoil the demonstration of Dick Benton's newly invented safety stop for trains seems certain of success when the locomotive is sent running wild down the tracks. Helen saves the day by climbing out on a wire stretching across the tracks and dropping to the speeding engine.

Blinded in a train accident James Driscoll (Holmes Herbert), whose wife, Miriam Driscoll (Belle Bennett), has been having an affair with his young male secretary Phillip Kingston )Carroll Nye), regains his eyesight. He keeps this from his wife, who continues her affair. Finally, he invites his young niece Nancy Driscoll (Josephine Borio) in the hopes she will fall for Philip and vice-versa. His ploy works, James reveals he can see again, and husband and wife are reconciled.

In a banana republic, way south of the Texas border, a dumb-Dora American girl, Norma (Olive Borden), lets her ruby-red lips promise more than she is willing to deliver, and she finds herself a prisoner in a notorious dance-hall/brothel. But her American aviator boyfriend, Barry Blake (John Boles), is flying to her rescue. He does just that but, alas, they are quickly captured by a gang of outlaws. Possibly the many expensive pieces of jewelry she has gathered from the many male friends she has made along the way, including El Presidente, captured the outlaws' attention.

H. Ulysses Watts is a traveling Shakespearean actor whose career is on the decline, as his audiences are more interested in cinema and vaudeville. When the troupe is robbed by Stoner, Watts cares for an injured young trapeze artist.

The owner of vast diamond mines, John Quelch is constantly fearful of theft and convinced that any woman will "sell her soul" for diamonds, he deals harshly with any employee caught stealing and has Lady Margot Cork watched while she is visiting Lorraine Temple. John and Margot fall in love, but she cancels their engagement when she learns of the "brutal" punishment of Jim Wingate for swallowing a diamond.

Patricia Reynolds, the belle of the summer resort she is visiting with her friend, Amy Powellson, attracts the attention of Arthur Kirby, whom Amy loves. On an evening drive, Arthur tries to kiss Patricia , whereupon she leaps from the car and walks home. While Amy, disguised in Patricia 's clothing, accompanies Arthur to a roadhouse, Patricia , walking near the beach, sees her invalid friend, Jim Wheeler, jump into the ocean intending to kill himself. After rescuing him, Patricia persuades Jim to visit a specialist, but when she later is accused of spending the night with Arthur, she refuses to defend herself in order to conceal Jim's attempted suicide.

The TARDIS crew lands in the Himalayas of Cathay in 1289, their ship badly damaged, and are picked up by Marco Polo's caravan on its way along the fabled Silk Road to see the Emperor Kublai Khan. The story concerns the Doctor and his companions' attempts to thwart the machinations of Tegana, who attempts to sabotage the caravan along its travels through the Pamir Plateau and across the treacherous Gobi Desert, and ultimately to assassinate Kublai Khan in Peking, at the height of his imperial power.