What is an inheritance? For the Welsh novelist Joe Dunthorne, the inheritance he received from his great-grandfather, Siegfried Merzbacher, came in the form of a bloodstone ring that had “escaped the Nazis” and a German passport. In his family history, Children of Radium, it is Siegfried’s story that Dunthorne sets out to tell. The story of a Jewish chemist who lived with his wife and two children in Berlin and injected radium into his gums in his efforts to develop a radioactive toothpaste. The story of the family’s escape to Turkey in 1935 to flee the Nazis, leaving everything behind. The story of their return to Berlin a year later, when, under the cover of the Summer Olympics, they carried out a heist of their own home. The story of the 12-year-old girl – Dunthorne’s future grandmother – smuggling family heirlooms from the attic, including the ring that would be a gift on his wedding day 80 years later. “No, it wasn’t like that,” Dunthorne’s unsentimental grandmother says when he quizzes her on this version of the family history. What was it like, then? Luckily, the facts are there, in the 2,000 pages of Siegfried’s memoir stashed away in a drawer, a document so long that no living member of the family had ever read it. They’re just not the facts Dunthorne wanted to read. Children of Radium is more than a memoir. It’s a detective thriller set in Berlin, Ankara and New York, as Dunthorne tries to track down the truth about his great-grandfather after nearly a century of distortions. It’s a book about what happens when a “comforting fantasy”, passed down through generations, is shattered by reality. It’s a lesson in history, chemistry and genocide studies, from radioactive toothpaste to chemical warfare. It is also, I should stress given the grimness of the subject matter, a funny, heart-warming and engaging page-turner. Dunthorne’s debut novel, the award-winning Submarine, was a tale of “mock GCSEs, sex and death”; he knows how to tell a good comic story – even if that story reveals your friendly refugee great-grandpa to be a man who inadvertently made poisoned gas for the Nazis. And that’s what Dunthorne discovers as he wades through Siegfried’s typewritten recollections. First, his Jewish great-grandfather really did work on radioactive toothpaste. But in 1928, Siegfried was asked to become director of a new chemical weapons laboratory in Oranienburg, along the river Havel, 40 minutes north on the S-Bahn from Berlin. He accepted, and spent the next seven years (before political developments forced him to flee to Turkey) developing ever-more toxic and efficient forms of poisons, including phosgene, diphenyl arsine chloride, and what the Germans called Lost – mustard gas. “You could not call any of this a family secret since it was right here, on very white paper, with half a dozen bound copies distributed among my relatives,” Dunthorne admits. When I read this, my mind immediately went to that old proverb that the best place to hide a tree is in a forest. Dunthorne decides that Siegfried is an unreliable narrator, and sets off to discover what really happened. Twice he visits Oranienburg, “Germany’s most radioactive town”, first with his pregnant wife and then solo, with a Geiger counter. He travels to the village of Ammendorf near Leipzig, where a nightclub now stands on the site of a former poisons factory, whose legacy can be felt in the cancers that residents of the town are still developing owing to decades of contamination. (“A little party never killed nobody” reads the slogan on the club’s Instagram page.) He notes the irony that chemical weapons were never deployed by Germany in the Second World War at the insistence of Hitler himself, who claimed to have suffered temporary blindness from mustard gas in 1918. “It created an uneasy situation in which my great-grandfather’s work might have been far more lethal without an intervention from Hitler.” Laced throughout his investigations is a sense not so much of inherited trauma, but inherited guilt. Siegfried was never able to fully confront or acknowledge what he was part of – the “confessions” in the memoir skirt around a subject too painful to articulate. Years later, psychiatrists in New York had no better luck unburdening a man whose entire personality had been warped by denial and anxiety. Can his great-grandson do any better? At several points on his journey, Dunthorne attempts to make amends. But again, reality gets in the way of a conventional narrative. At Ammendorf, he shows Erich – an octogenarian activist who has spent decades campaigning on behalf of contamination victims – the pages Siegfried wrote regretting his work on chemical weapons. The campaigner can only respond: “On behalf of all Germans, I apologise.” “I should have understood that Erich would not accept remorse from a Jewish chemist,” Dunthorne writes. “In the silence that followed I realised that there was no way for us to speak across these tangled pasts, one history making it impossible to acknowledge the other.” Even the seemingly straightforward part of the story, the family’s life as refugees in Turkey, is complicated. I won’t explain why Dunthorne visits the site where, in 1938, the Turkish government massacred Kurdish rebels using poison gas bought from the Nazis. Needless to say, the experience does not present our author with the absolution he had hoped for. There is no exoneration. There is, though, a reminder of what it meant to be Jewish and German in the 1930s: smashed synagogues, statelessness, loved ones sent to Auschwitz. This is still a Holocaust book. I read Children of Radium on a flight to Berlin. It was my first time visiting the city where, around the same time Dunthorne’s great-grandfather was mixing toxic compounds to make them more deadly, my own Jewish grandfather, Opa, and his siblings were planning their departure. It was my first time entering Germany on the German passport I applied for after Brexit, making use of my right to the citizenship my grandfather had never reclaimed – something Dunthorne does himself in the course of this narrative. And I had a ring as well, one that belonged to my great-aunt, who, unlike her brothers, did not escape the Nazis. I remember realising that the story I had been told about my great-aunt as a child had gaps in it, that I must have been given a sanitised version. Maybe that’s true for every descendant of a Holocaust survivor. The details too dark to share with the children are omitted, until the children grow up and there is no one living who remembers what the real details were. The process for obtaining German citizenship involves turning up at the embassy in Belgravia to receive the certificate in person. I know this because in June 2019 my mother, sister and I did just that. We were handed our citizenship certificates by a friendly but serious embassy official called Julianne. I had no idea when I began Children of Radium that Julianne would feature, solemnly presenting certificates to Dunthorne and his family. When she asks what his grandmother would have thought of their citizenship, Dunthorne’s mother admits she wouldn’t have liked it. “Julianne looked pleased at this answer, perhaps because – in acknowledging that our becoming German was problematic – my mother was being distinctly German.” “Problematic” feels at once too strong and too small a word to describe the process of “becoming German”. (For what it’s worth, I have always felt that Opa would have approved of being able to give me and any future children I might have the freedom and security that comes with citizenship of another country. But perhaps that is wishful thinking.) Lofty sentiments of restoration and righting historical wrongs are complicated by the fact that, like me, Dunthorne only wanted to become German to get an EU passport after Brexit. “It felt deeply meaningful and completely dishonest at exactly the same time,” he writes. I know exactly what he means. You don’t need a personal stake in this period of history to be moved, horrified and entertained by Dunthorne’s story, which is full of bizarre juxtapositions too strange to be fiction. What he has inherited is darker and more sinister than he could have expected. But he has gained the understanding of who his great-grandfather really was – neither hero nor monster, just a flawed, anxious, “problematic” man – and all the cross-generational ways in which he lives on. Dunthorne’s own children now have German passports. The question is, when they ask about how they got them, what story will they be told? Children of RadiumJoe DunthorneHamish Hamilton, 320pp, £16.99 Purchasing a book may earn the NS a commission from Bookshop.org, who support independent bookshops