The Californios by Louis L'Amour is the tale of the Mulkerin family's struggle to keep their ranch after an unscrupulous man buys their bank note and wants to foreclose for his personal gain.

The story takes place in 1844 when Southern California was sparsely inhabited. The towns and cities were few and largely undeveloped. The ranch was a typical type of home and horses and wild animals abound. There is a lot of talk of riding off into the wilderness and travel.

The story speaks about Malibu, the home to the Mulkerins. The area is relatively rural at this time and it is clear that the region is still somewhat rough-hewn and unsettled. The author describes Malibu in such a way that the reader can relate it to the modern day Malibu, at least as far as the scenery goes. There are many hills and breathtaking views of the Pacific Ocean.

The Mulkerin Ranch House is located in the mountains of Malibu. The house is a low-roofed adobe that has been added onto over the years. Near the open porch is a lean-to stable. From the front porch one can see hills, boulders and sandstone outcroppings.

Not far from the ranch are mountains, canyons and the open desert. The Mulkerins spend time in the mountains looking for gold. There are few that know the mountains well, even the trackers. The only one that seems to know every inch of the hills is Juan, The Old One.

The story begins with a man named Wooston who has purchased the bank note on the Mulkerin ranch. The ranch is home to Eileen Mulkerin and her sons, Michael and Sean. Michael has joined the Church and Sean is usually out to sea, but it is still the family home and all that Eileen has left of her deceased husband, Jaime.

Sean Mulkerin is trying to raise enough money to pay off the bank note. While in Acapulco, a woman swims out to Sean's boat and insists that he take her far away or there will be trouble. The woman, Mariana, is running away from her betrothed, a violent and powerful man.

Sean takes Mariana back to the ranch to meet Eileen and the others.

No matter what Eileen does, it seems that there is no way to raise enough money to pay off the bank note. Still, Eileen is determined to save the ranch and promises trouble to any that try to stop her.

Zeke Wooston is the owner of the note and will do anything to get his hands on the land, mainly because he wants use of Paradise Cove, an old smuggler's port. Wooston employs many men, all of which are of questionable character.

Eileen decides that the only way to save the ranch is to ride into the hills to find Juan, Jaime's old friend, and most likely the only man that knows where to find gold.

Juan, The Old One, is a mystical man with great wisdom. He leads Eileen to the gold but there is not enough to pay off the debt. Along the way, Juan dies. The rest of the party is followed by eight men, but they manage to make it back to the ranch.

One of the men, Russell, encounters the spirits and is punished for his misdeeds.

Eileen's plan for a fandango is a good one as long as Wooston bows to peer pressure. Wooston is not to be discouraged however. He sends two men to kill Sean, but they fail. Back at the ranch, Wooston waits for the Senora. Thinking that he has killed Sean, Wooston is sure the ranch is now in his possession. Wooston is wrong and is killed by Sean.

In the end, the Unknown ones shine on the Mulkerins, giving them a jar full of gold that will surely save and revive the ranch.

The main plot of the story is the fight to keep land and ward off unscrupulous outlaws and politicians while searching for gold. The subplots include Eileen's history and relationship with her dead husband Jaime as well as her pride and self-reliance. There is the story of Sean and Mariana and their blooming relationship. Lastly there are many references to spirits and hauntings of the land, which lends an air of mystery and intrigue to an otherwise common battle to protect one's home and family.