The Drift Latitudes, by Jamal Mahjoub

There are three main stories in Jamal Mahjoub's novel The Drift Latitudes - those of Ernst Frager, a German immigrant to Britain in the 1930s, and of his two daughters by different mothers, Rachel and Jade. Added to this are several subsidiary ones, such as that of Ismail Bilal, who owns the jazz club where Ernst met Jade's mother but has nothing to do with the rest of the story.

Rachel's mother is rich and white, Jade's poor and black. Rachel marries Amin and returns to Sudan, where she loses him and their son Sayf to Islam. Jade remakes herself as a successful architect, until she loses her job to an even pushier white woman.

Thus we get cross-culture and cross-class marriages, and struggles with the ancient world (Rachel) and the modern one (Jade). All this too often leaves time for only perfunctory portraits: of Ernst's neurasthenic wife Edith; or of Jade's green, vegetarian teenage daughter, whom she neglects.

Ernst has stock German experiences - wartime internment, suspicion - but nothing German about him. He never gives a thought to Germany's war, and could come from anywhere. So could Jade, little different from her white rival - ambitious, deracinated, cold. The only true and moving story is Rachel's, as she waters the dusty plants in her Khartoum garden, grieving for Sayf, killed in the civil war.

Though there are too many stories, too little is told. Even Rachel's chapters are at first obscure - it takes time to work out they are letters to her sister. And in the dramatic opening pages, Ernst lets his car "glide silently down towards the battered bronze shield" of the sea. "Suicide", you think; but you're wrong. This is complication for its own sake: ambition, like Jade's, not the simple need to tell a tale, like Rachel's. Ambition is the problem. The Drift Latitudes is a reference to Wide Sargasso Sea (Jade hints), but Mahjoub has not learned from Jean Rhys.

The novel is meant to be about refugees over the generations, as Mahjoub signals in the sisters' visions: Rachel watching poor marsh-dwellers passing her gate, Jade among the illegal immigrants of London. But Jade's vision does not connect to the real world, and neither does Mahjoub's. He never mentions the real refugees from Germany, anti-Nazis and Jews; and Rachel is not a refugee, but someone who married for love.

The only real refugee is Ismail Bilal. Maybe that's why he's there after all.