Spring, 1865. The last spring in the childhood of Lukas Bienmann. Nothing forebodes the calamities about to befall the 13-year-old boy and his family in the peaceful town of Liebenberg, Prussia. Nature awakens to new life, and Lukas is happy, for his mother is about to give birth to her second child, and Lukas' grandfather, Brunneck, is coming from Canada for the event. Brunneck, however, brings only discord to the family. Though Lukas is excited by his grandfather's plans to take the family back with him to Canada, his father Karl will hear none of this. Tempers flare and Lukas' mother, deeply troubled and frightened, goes into early labor - and dies. Brunneck blames Karl, and demands to take Lukas with him. Bewildered, Lukas flees into the night. Lukas accidentally witnesses an altercation between a local nobleman, Count Otto von Lebrecht, and a gambling partner to whom he owes money. When Otto kills the man in a rage, Lukas tries to flee, but is caught by the murderer. Otto threatens to kill him and his father should he ever talk... Otto, who has stolen some valuable jewels, lays the blame on Lukas' father Karl. Fearful of Otto's threats, Lukas is unable to defend his father, even though he knows that Otto committed the theft. After Karl is sent to jail, Lukas is taken into the home of the benevolent Baron von Knabig. The Baron places the boy in the custody of his wife's brother - who turns out to be none other than Otto von Lebrecht! Though Lukas' future looks bleak, he soon wins the confidence of the Baron and his wife: one day, Al-Jamil, the magnificent stallion the Baron has bought for his daughter Ursula, is whipped into a panic by Count Otto. Lukas leaps into the paddock to calm the animal and prevent it from injuring anyone. Impressed, the Baron entrusts Al-Jamil to the boy's care. Though Ursula, fifteen, is not allowed to ride Al-Jamil yet, she disobeys her father and is nearly trampled by the frisky stallion. Lukas rescues her, and is rewarded by being allowed to visit his father in prison. Otto, however, foils the meeting, just as he has been preventing the Baroness' letters from reaching Brunneck in Canada, ensuring that the boy's grandfather cannot come to his aid. Unable to pawn the stolen jewels, Otto plots to kidnap and sell Al-Jamil, and to dispose of Lukas in the process. Otto puts a wrench in his own plans, however, for he causes an accident in which the horse is seriously injured. The Baron wants to have the horse killed, but Lukas begs him to let him nurse Al-Jamil to health. Ursula, won over by Lukas' energetic nature, finally brings her father to yield. Al-Jamil's recovery helps seal Lukas' friendship with Ursula. As Otto's threats become more menacing, Lukas plans a daring escape for himself and his father. To this effect, he enlists the help of an old peddlar and trusted friend, Nathan. Though they succeed in freeing Karl from prison, the operation runs into a snag when Otto's henchmen capture Lukas. While Karl heads off to America alone, Lukas frees himself and gallops to Danzig on Al-Jamil. He sneaks onto a ship headed for America, hoping to find his father there. Little does he know who else is on board: Ursula, the Baroness - and Count Otto. Lukas is discovered and faces punishment as a stowaway. Sensing that the boy is troubled, the Baroness takes him aside. Lukas pours out his heart and reveals the truth about Otto... Determined to clear Karl's name and save Lukas from punishment, the Baroness confronts Otto, who confesses. Before she can bring the truth to light, however, tragedy strikes: smallpox breaks out among the passengers, and she succumbs to the disease while caring for the sick. Meanwhile, Karl arrives in the American South, where he is hired by a northern lumber company to take a shipment of wood north. He and his companions Virgil and six-year-old Tomorrow, ex-slaves, are being followed by Tully, a Southerner bent on destroying the lumber dealer. One night, Tully sets fire to the depot where Karl and the others are sleeping. A fight ensues, and Tully is engulfed by the flames. Karl tries to save Tomorrow, but is too late: the boy dies in his arms. Shattered by her mother's death, Ursula resolves to help Lukas now that she knows about her uncle's murderous past. As the ship anchors in New York, the children violate the quarantine and jump ship, with Otto fast behind them. They elude Otto, but fall into the hands of two con men, who take them to Lower Canada, where they plan to ransom Ursula and kill Lukas. But Lukas discovers their plan, frees Ursula, and they escape down river in a canoe. Their troubles are far from over, however, for the quiet, tranquil river soon gives way to churning, foaming rapids. The children lose control of the canoe, which overturns, submerging them. Lukas dives after Ursula, pulls her to the surface, and drags her to the shore. Exhausted after their ordeal, the youngsters now find themselves alone on land best avoided by white people: Indian territory. Lost in the wilderness, Lukas and Ursula decide to head for Brunneck's house in Niagara. But disaster strikes again when a bear attacks and mauls Lukas. Ursula's screams alert some nearby Indians, who shoot the bear as it is about to kill Lukas. The children are taken to the Indians' camp, where Lukas comes under the care of a medicine man. Karl makes it to Niagara, where he begs his father-in-law to send for Lukas. Brunneck agrees, however, only on the condition that he be given responsibility for Lukas' upbringing. With his son's well-being at heart, Karl accepts Brunneck's terms and leaves. But when Brunneck learns the children's whereabouts and Lukas arrives in Niagara, Brunneck tells him that his father has left him in his care, implying that Karl no longer wants him... Thunderstruck, Lukas turns his back on Brunneck. He and Ursula set out by rail for the West. The train nearly turns into a death trap, however, when they run into Otto. With their lives at stake, they jump from the train and continue their journey on foot. The weary pair is picked up by a wagon train, and befriended by Renauld and Françoise Broissard. Ursula, meanwhile, catches the eye of a good-looking railroad surveyor named Ben. Lukas and Ursula soon realize how dangerous pioneer life can be when a messenger warns them of approaching hostile Sioux warriors. Fearing the worst, Françoise sends a message to Brunneck. Lukas believes that he can talk sense into the Indians and, disobeying Ben's orders, impulsively sets off on horseback to find them. Ben catches Lukas and berates him, but their argument comes to a sudden end when the Sioux appear on a nearby ridge... Blood-curdling cries announce the Sioux' charge. When Ben is injured, Lukas grabs his fallen comrade's weapon and joins actively in the skirmish. His enthusiasm for the battle vanishes, however, when he suddenly faces a knife-wielding Sioux youth and kills the boy in self-defense. The settlers manage to drive away the Indians, but Lukas cannot overcome the shock of having taken a person's life. Brunneck, who has gotten Françoise's message, swallows his pride and asks Karl to go look for the children with him. A short time later, Baron von Knabig also arrives in Niagara and sets out for Fort Garry as well. At Fort Garry, Lukas is moved by the plight of a pregnant young Cree woman, White Feather, who is being mistreated by her white husband Sam. Unable to take the life-threatening abuse of the young woman any longer, Lukas decides to smuggle her out of the fort and back to her tribe. Though Ursula tries to talk him out of it, nothing can deter him. The escape goes like clockwork. But just before the pair can reach the Cree camp, the girl goes into labor, giving birth to a baby boy. Suddenly, Sam appears, filled with a murderous desire for revenge. Fortunately, a Cree hunting party disarms him. Though White Feather is saved, Lukas makes an unpleasant discovery: the Cree are accompanied by two Sioux warriors who attacked the wagon train - and who also recognize Lukas... Lukas is brought to the Cree camp, where the Sioux demand his life. But the Cree Chief, grateful to the boy for having saved White Feather, gives Lukas a pony and orders Black Hawk to escort him to Fort Garry. On the way, Black Hawk forces Lukas into a perilous race. But when the boy holds his own, a bond begins to develop between the two - a bond which is cemented when Lukas saves his companion's life in an Indian attack. Brunneck and Karl have been robbed by a trapper and abandoned in the wilderness. When a wildfire breaks out, the two men finally reconcile their differences and fight to save their lives. Close to exhaustion, they are saved by none other than Baron von Knabig and a wagon train headed for Fort Garry. The Baron is reunited with Ursula, but his companions set off with Black Hawk, who was forced to leave his friend Lukas behind in the Indian attack. Count Otto is also out West. He has taken on the identity of Clayton Pyle, who was on his way to claim half a gold mine he inherited with an aunt he never met. The injured Lukas comes across the prospector Annie Pyle, who takes him to her gold mine. Lukas' blood freezes when he meets "Clayton". Otto shoots, causing a cave-in, from which they barely manage to escape. Undaunted, Otto again goes after Lukas and tries to drown him, but just before he can do so, Black Hawk comes galloping to the rescue and kills him. Ursula, who is in love with Ben, is afraid that her father will take her back to Prussia. But the Baron, much to her surprise, agrees to cancel the marriage he had planned for her and gives the couple his blessing. Karl and Brunneck are overwhelmed with joy when they spot Lukas approaching with Black Hawk. After so many trials and tribulations, the family is finally reunited once again.