Grand Duke Leonid of Russia is in Washington to sign a commercial treaty on behalf of the Tsar. But this larger-than-life aristocrat has read too much Fennimore Cooper and wants to visit the West. The US government is forced to agree to his whim - but wisely chooses Lucky Luke to escort him to the cattle capital of the West: Abilene. A good thing too, because the Russian Grand Duke encounters real American desperados on his visit!