Blooms of Darkness, By Aharon Appelfeld, trans. Jeffrey M Green

Aharon Appelfeld survived the Holocaust as a child, living like a wild boy in the forests of Ukraine. His remarkable memoir, The Story of a Life, tells how he briefly found shelter with a woman called Maria, the village prostitute. Maria drank, and was often despairing, but when she was happy she filled the hut with light. At these times she seemed like the smiling girl in a picture above her bed: perhaps, Appelfeld wrote, that was how she wanted to be remembered. That is how he remembers her here. Blooms of Darkness is a work of imagination, but at heart the story of Mariana is surely the story of Maria. And though Appelfeld has not forgotten her dark side, he remembers her beauty and gaiety much more.

The story starts on Hugo's 11th birthday, in a Ukrainian ghetto. Deportations are gaining pace; his father has disappeared. One night his mother takes him through the sewers to her friend, Mariana, who has "fallen low". Hugo doesn't understand what this means;. There his mother leaves him. He never sees her again, except in dreams.

For the next year and a half, Hugo spends his days locked in Mariana's closet, hearing her encounters with her clients, her drinking, her joy and despair; and his nights being warmed in Mariana's bed and washed in her scented tub. Slowly his parents recede from him, and love for Mariana takes over. He lives in a torment of fear and sexual pleasure; until the war ends, and they flee together to the mountains. Now the roles are reversed. Hugo is safe, but Mariana, who served the Germans, is in grave danger.

The combination of disturbing sexuality and the Holocaust has always been dubious, from The Night Porter in 1974 to Jonathan Littell's The Kindly Ones in 2006. Blooms of Darkness may sound the same, and sex with a child is one of our most sacred taboos. But it is not the same at all.

Too often, in the others, the sex seems to be the point. Here the point is the nature of memory, the growth of a writer, and above all the psychology of persecution and survival. The parents' dilemma of how to live with horror, and what to tell the children; Hugo's inexorable forgetting; the inability to understand what you fear – for Hugo, the meaning of "whore", for survivors, the fact that most will never return – all are caught in Appelfeld's glancing, delicate prose.

He asks two main questions. First, why are people persecuted? Kitty, for example: a young whore whose innocence shames the others, until one savagely beats her. The girls agree the Jews are more delicate – politer, gentler – than non-Jews among their clients. Bitterly, Hugo asks, "Are they persecuted because of their delicacy?" The case of Kitty shows that at least part of the answer is: yes.

Second, how can the persecuted survive? They should not despair: that is the message his mother, Julia, leaves to Hugo. And they should not fear: that is Mariana's message to him. As his Aunt Frieda said, "There is always someone who loves you"; and as Appelfeld shows, there is always someone to love. It is love that gave Julia the courage to save her son, and love that makes Mariana equally brave and selfless at the end. Neither survives physically; but that is not what this book means by survival. You can't get much further from The Night Porter than that.

Carole Angier's 'Primo Levi: The Double Bond' is published by Penguin