James McAvoy, in his best performance so far, plays young Valentin Bulgakov. Like many of young men and women of his generation, he feels a bizarre affinity to the Tolstoyan philosophy and is offered the job of a lifetime by Vladimir Chertkov (Paul Giamatti in his usual Paul Giamatti shtick) to be Tolstoy's private secretary. But there is a caveat: he needs to keep a diary of the goings-on within the Tolstoy household without the knowledge of the big man or his wife Sofya (Helen Mirren in her usual brilliance). Chertkov, who is in house-arrest in Moscow, wants to ensure that Tolstoy relinquishes the rights to his work for humanity's benefit, while Sofya Tolstaya wants her husband's money and work to remain in the family hands.
Valentin is all giddy with excitement upon meting Tolstoy, but his initial excitement gives way to other urges. He falls in love with a fellow Tolstoyan "volunteer", Masha (Kerry Condon), whose free-spirit is at odds with the Philosophy. Their indiscretion, to Valentin's surprsie, is approved of by the big man. However, more troubling for Valentin is the way Sofya is treated by the myriad of people surrounding her husband, including her daughter.
