Beginning in 1939, young Solly in London exchanges letters with his teenaged cousin, Bernie, in Poland.
While Solly is evacuated and tries his best to adjust to life in the English countryside, Bernie's parents know that as Jews they're not safe staying in Warsaw, so they send Bernie to the Russian-occupied side of the country in the hope that he'll be safer there.
Soon, though, he is arrested and sent off to a forced labour camp in Russia.
As the cousins exchange sporadic letters, they try to keep their spirits up, trading jokes and observations about the world changing all around them.
Then Bernie seizes the opportunity to join the "Anders Army" and fight the Axis powers, and tells Solly all about his experiences in Iran and eventually Italy, where he fights alongside the British at the famous Battle of Monte Cassino.
Does Bernie survive and find a safe place to call home?