Based on the life of the illustrator, Only the Heart tells the story of Toan and his family who escape Vietnam by boat. The story covers events in his life as a six-year-old and then as a teenager. Diary-like entries of two cousins and several other characters adds realism. The story is a gripping one of survival and coping with the consequences of war.

1. Immigration
2. Refugees
3. Resilience
4. War