Olga Pushkin - railway engineer and would-be bestselling author - spends her days in a little rail-side hut with only Dmitri the hedgehog for company. However, one day Olga arrives at her hut only to be knocked unconscious by a man falling from the Trans-Siberian Express, an American tourist with his throat cut from ear to ear and his mouth stuffed with 10-ruble coins. Another death soon follows, and Sergeant Vassily Marushkin, the brooding, enigmatic policeman who takes on the case, finds himself falsely imprisoned by his Machiavellian superior, Chief-Inspector Babikov. Olga resolves to help Vassily by proving his innocence. But with no leads to follow and time running out, has Olga bitten off more than she can chew?