The State Counsellor(2005)

The State Counsellor is a Russian historical thriller following detective Erast Fandorin as he races to solve a murder aboard a speeding train from St. Petersburg to Moscow. When General Khrapov is found stabbed in his compartment, a cryptic "BG" mark on the blade points to an elusive terrorist organization. Fandorin, the empire's most capable investigator, takes the case—but he's not alone. Prince Pozharsky, a rival investigator with his own agenda, complicates the pursuit. As the train hurtles through the Russian landscape, the two men clash in a deadly game of wits and honor, each determined to catch the killer first. Tension mounts as secrets unravel and the conspiracy deepens, threatening far more than one general's life.