One evening, 10-year-old Louisa and her father take a walk out on the breakwater. They are spending the summer in a coastal Japanese town while her father Serk, a Korean émigré, completes an academic secondment from his American university. When Louisa wakes hours later, she has washed up on the beach and her father is missing, probably drowned.

The disappearance of Louisa’s father shatters their small family unit. As Louisa and her American mother Anne return to the US, this traumatic event reverberates across time and space, and the mystery of what really happened to Serk slowly unravels.

Flashlight moves between the post-war Korean immigrant community in Japan, to suburban America, and the North Korean regime, to tell the astonishing story of one family swept up in the tides of 20th-century history.