Driven by a deep sense of duty and a love for his country, Damien (Cillian Murphy) abandons his burgeoning career as a doctor and joins his brother, Teddy in a dangerous and violent fight for freedom. As the Irish freedom fighters bold tactics bring the British to a breaking point, both sides finally agree to a treaty to end the bloodshed. But, despite the apparent victory, civil war erupts and families who fought side by side, find themselves pitted against one another, putting their loyalties to the ultimate test.