Three days after Russian tanks roll into Ukraine, President Volodymr Zelensky issues a desperate appeal for foreign military volunteers to help defend his country. Thousands answer the call from all over the world: some of them experienced soldiers, others novices who’ve never held a gun before.

Among their ranks are high-minded idealists, adventure-seekers bored with civilian life, and ex-criminals seeking redemption – all risking their lives against the world's most vicious superpower. Some flee at the first sign of trouble, others become heroes; many are killed, and a few turn their guns on each other.