The Enterprise arrives at Chicota Landing with a cargo of gunpowder for the Army. Before they can unload it, the boat is taken over by a gang of Mexican bandits led by Juan Cortilla.

To Captain Holden, his romance with Marie Tourette was just a pleasant interlude, until he discovers she is passing him off as her fiancé. While her family is in on the deception, they expect Grey to follow through and marry

In town to have an aching tooth removed, Carney stops at the saloon for a bolstering drink. This makes him late for the dentist, so Blake undertakes to separate Carney from his tooth.

Sir Oliver Garnett and Juliet, his young companion, are shipwrecked actors. Captain Holden fishes them out of the river and books them as entertainers aboard the Enterprise.

Fast talking Martinus Van der Brig persuades Holden and Bill Blake, the riverboat's new pilot, to transport a group of pioneers to some new territory, recently purchased from Mr. Van der Brig.

If Grey will lure a belle named Lucinda away from Colonel Ashley's son Tony, the colonel will provide a profitable cotton cargo for the Enterprise. Unfortunately, Lucinda overhears the proposition.

Norwegian songbird Julie Lang wants to take her troupe to New Orleans for an engagement, but she has no money. Grey finally agrees to take the troupe aboard the Enterprise, for an IOU against their New Orleans receipts. Along the way, a future crewman of another famous ship called Enterprise, steals her jewelry.

For a price, simple-minded Hunk Farber is only happy to reveal the whereabouts of his boss, Monte, who accidentally killed a senator's son. The reward in his pocket, Hunk heads for Captain Holden's riverboat. There he is eager to impress a young lady aboard the Enterprise.

Young Jefferson Carruthers has been assigned to a new post as an Indian agent. He and his wife board the Enterprise to travel to their new home. Also on board is Vance Muldoon, who plans to offer Carruthers money if he will smuggle liquor to the Indians.

Wealthy Roger Mowbray's marriage is threatened when an old sweetheart intimates that Roger married for money. Because he really loves his wife, Roger is doubly upset to discover that his father seems to be involved in the scheme to break up the marriage.

John Jenkins has placed a large down payment on land owned by three ruthless farmers. Jenkins is planning to deliver a shipment of peaches, via the Enterprise, to Cincinnati, as a final payment for the land. But the farmers plot to block the boat so the shipment of peaches will be spoiled.

Riverboat pilot John Murrell plans to hijack a shipment from rival pilot Dan Simpson. Murrell arranges to have Lela Candida take a job on Simpson's boat as a dancing girl, so that she can signal his raiders when to attack.

Ansel Torgin hires the Enterprise for his daughter's wedding. Captain Grey Holden recognizes the bridegroom as a drifter he once threw off his riverboat.

Laura Sutton is forced to kill her husband in self defense. Laura's brother-in-law, Jarrett Sutton, witnesses the shooting and tries to blackmail her.

Otto Justin, dealer in wild animals, is escorting a shipment of his captured beasts to St. Louis aboard the Enterprise. Widow Abby Saunders and her young son Paddy are both impressed with Justin's manner.

French playboy Andre Devereaux has become an American lieutenant. Assigned to lead some troops into Indian Territory, he finds that the normally peaceful Indians have been provoked to violence.

Prisoner Paul Drake is being returned to custody by a prison guard. Because Drake has already tricked him once, the guard shackles his prisoner to a deckhouse on the Enterprise.

Tommy Jones, a young stowaway, is discovered aboard the Enterprise. Also on board is a pair of thieves, who plan to blow up the boat to collect insurance on some diamonds they are shipping to St. Louis.

Lt. Perry Quinn, an officer in Sam Houston's Texas Army, hires the Enterprise to deliver a cargo of lead down river. Captain Grey Holden is warned that Santa Ana's agents may try to sabotage the shipment.

Actress Lorna Langton wants to charter the Enterprise and a skeleton crew for a trip to St. Louis. The actress has been told that her young son, kidnapped some years before, is being held in another town.

Anthony Lorrimer charters the Enterprise to deliver a cargo of farm machinery to his thriving community of Lorrimer City. Captain Grey Holden is unaware that the cargo is actually arms and ammunition.

The Enterprise steams upriver with a cargo of arms and recruits for the Fort Union outpost. At Akins Landing, Grey Holden is told by Homer Atkins that the Sioux have been watching the boat and are planning an uprising.

A group of volunteer teachers who have gone to the island of Diablo Corozan off the coast of Tampico are imprisoned when Spain conquers the island. The corrupt Spanish officials allow Joan Marchland, one of the teachers, to return to the United States to raise a ransom for the rest.

The Enterprise, tied up overnight, is boarded and highjacked by a vicious crew, who kill the three men left to guard the boat. Captain Grey Holden and Ben Fraser return to the scene in time to see their craft heading down the river. They set out overland to head her off.

Captain Grey Holden and his crew get into a street brawl over Martha Crane and land in jail. Martha agrees to bail them out on the condition that Grey will transport a supply of gunpowder up river to her father.