Fethiye Cetin was a student when she discovered her grandmother's secret. Until then, she'd always known the woman who brought her up as Seher, the pillar of what seemed a typical Anatolian family.
The bombshell came while the two were talking one day in Ankara. Seher's real name was Heranush, and she was Armenian. Nine years old when the little-known massacre of Armenians started in 1915, she had cowered in a churchyard as the village men were murdered and thrown in the river. Forced with the women and children onto the road to Syria, she was abducted and handed over to a police corporal who brought her up as his own child.
Such tales are common in Turkey's eastern provinces. What makes Heranush's story unusual is that her granddaughter decided to turn it into a book.
'She had hidden the things she told me for over 60 years,' explains Ms Cetin, now a lawyer based in Istanbul. 'I felt they needed to be given a voice.'
But Ms Cetin also wanted to help move the debate away from barren disputes over statistics and terminology: 300,000 killed? No, 1 million. Genocide? No, ethnic cleansing.
Such arguments, she says, 'hide the lives and deaths of individuals and do nothing to encourage people to listen'.
Turks have certainly been listening to her. Published last November, My Grandmother is already in its fifth edition.