A young woman tries to solve a family tragedy in this earnest outing from Davidson (Under the Salvadoran Sun). Lena Larsson grows up in Astoria, Ore., with her widowed mother, Sofia, and Swedish immigrant grandmother, Helga. Every night, Helga screams in her sleep. In 1961, when Lena is nine, Sofia tells her the screams have been happening ever since Helga returned from a 1939 visit to Sweden, but Helga refuses to say what happened there. Then, when Lena is 16, Helga dies by suicide, taking her secret with her. Lena goes on to win a scholarship at the Sorbonne in 1973, and after Sofia dies of cancer, Lena decides to visit her extended family in Sweden, a trip that she and her mother always dreamed of taking together. Hanna, the second wife of her recently deceased great-uncle, welcomes her and endures her insistent questioning about what her grandmother witnessed. What surfaces is a complicated story of the death of her Jewish great-aunt, which proves more shocking than she’d imagined. Though the dialogue and exposition can feel a bit stilted, Davidson does a nice job unfolding the mystery. The sound plotting makes this worthwhile. (Self-published)