Flashlight by Susan Choi

BookBar says: Ten year-old Louisa is found washed up and alone on a Japanese beach with her father Serk presumed drowned. Set across decades and continents, Flashlight follows the fates of the Kang family from wartime Japan to modern day California and is part family saga, part crime thriller and part historical novel. It's completely gripping and compulsive, another excellent title longlisted for this year's Booker Prize.
 
'Ferociously smart and full of surprises' ELEANOR CATTON, author of Birnam Wood. 'Instantly bewitching' JENNIFER EGAN, author of A Visit From the Goon Squad