Plot Summary: Lev Glebovich Ganin immigrates to Berlin due to the Russian Revolution and subsequently moves into a boarding house where he learns that one of his house mates is Aleksey Ivanovich Alfyorov. It turns out that Alfyorov is the husband of Mary, Ganin’s first love. Consequently, Ganin breaks up with his current girlfriend, because he’s absorbed with memories of Mary.
Maurice Couturier added in Nabokov's Eros and the Poetics of Desire: "In Mary, his first novel, Nabokov represented the idyll of two adolescents discovering together the joys of sex and the seductions of love.” (272)
Mary is an anomaly, because the novella doesn’t contain any clear examples of nympholepsy, which shouldn’t be surprising since it was Nabokov’s first book. However, Mary was written and first published when Nabokov was in his late twenties and according to Boyd’s Vladimir Nabokov: The Russian Years, Mary is based on Valentina (Lyussya) Evgenievna Shulgin, a fifteen-year-old Russian nymphet. (112)
And in chapter six of Mary: “a student medical orderly at the local military hospital” had a “fifteen-year-old 'sweet and remarkable' girl". (60)
Boyd, Brian. Vladimir Nabokov: The Russian Years. Vintage, 1993.
Nabokov, Vladimir. Mary. Translated by Michael Glenny, Penguin Classics, 2012.