Thank You, Mr. Moto

A caravan sets out across the Gobi Desert, where a man sneaks into a tent intending to steal a valuable scroll. Moto is secretly awake and kills the thief to protect the scroll, signaling his cunning and discreet nature. The scene establishes Moto's involvement with valuable and dangerous artifacts from the very beginning.

The caravan arrives in Peiping, where Moto undergoes a police search. The authorities find the scroll he's carrying, but Moto swiftly seizes the opportunity to escape, showcasing his agility and resourcefulness. This move puts him on a collision course with other treasure hunters and villains.

Moto changes clothes and accepts an invitation to a social gathering hosted by Colonel Tchernov, which is in honor of American Eleanor Joyce. During the party, Moto observes Prince Chung leaving a room in private conversation with Tchernov, indicating covert dealings and the presence of valuable heirloom scrolls.

Tchernov tries to buy family heirloom scrolls from Prince Chung, but Chung refuses. Tchernov then draws a pistol, but Moto intervenes and kills Tchernov, staging his death to appear as a suicide. This act consolidates Moto's reputation as a dangerous and skilled man of action.

Prince Chung confides in Moto about the seven scrolls that contain directions to Genghis Khan's lost treasure and tomb. However, one scroll was lent to an exhibition and subsequently stolen, intensifying the quest for the treasure.

Joyce expresses interest in a scroll that turns out to be fake while shopping with Tom Nelson. Later, they see Moto confront Pereira and learn that Pereira has stolen the authentic scroll. Before Moto can gather more details, Pereira is murdered by a gunman fleeing the scene.

Moto returns to his apartment and finds it invaded by intruders. Schneider holds him hostage at gunpoint, coercing him into surrendering the scroll. An attempt to escape fails when Schneider shoots Moto with blanks, showing Moto's resilience and cunning in dangerous situations.

Moto follows Schneider to Madame Tchernov's location but is knocked out by Ivan, the butler. Joyce is taken hostage, leading to a tense standoff with Tchernov's gang, which reveals the extent of their involvement in the treasure hunt and illegal dealings.

Herr Koerger tortures Prince Chung to obtain the location of the scrolls, resulting in the prince's death after his mother is killed defending him. Nelson revives Moto, and they rush to aid Prince Chung, but arrive too late, and the prince takes his own life out of dishonor.

Moto and Nelson follow the criminals aboard a junk, engaging in a tense chase that culminates in Moto revealing that one of the scrolls is a fake. He uses this to sow distrust among the villains and plan his next move for the treasure.

Moto confronts Koerger and warns him that the scroll he possesses is a fake. After deceiving Koerger with false information about the treasure, Moto kills him and destroys the scrolls, fulfilling his promise to Prince Chung and preventing the criminals from claiming the treasure.

With the scrolls burned, Moto ensures that Genghis Khan's treasure remains hidden. The events resolve with Joyce and Nelson witnessing Moto's final act of safeguarding the secret, emphasizing his role as a protector of the treasure's resting place.