Just as 18-year-old Londoner Erin sets off to spend summer in Israel with her best friend, Eliza, she unearths an old diary belonging to her seriously ill grandfather, Len. Intrigued by the life of this old man she barely knows, she takes the diary with her, and is stunned to learn of his part in the post-WWII British peace-keeping force in what was then Palestine.
In 1947, Jews are out on the streets celebrating the British withdrawal from Palestine and in Haifa, the exodus of Arabs has started and Len is worried about the safety of Mohammed and his family and Erin discovers her grandfather's shame. Erin refuses to give up her quest to find Mohammed's family, even when it takes her on a dangerous journey into Gaza.