Growing up together in the early 1900s in the London Docklands, Harry and Karl forge an unbreakable friendship. With their fathers working as dockhands, both families struggle to survive on low wages and poor living conditions.

Facing unemployment and destitution following a dock strike in Germany, Karls parents moved to England for a better life, hoping to raise their son in an environment of love and security. However, Harrys homelife is dominated by violence and drunken cruelty inflicted by his father. Shared dreams of a life far away from the grime and deprivation of the shipyards see the two friends swear a lifetime oath of allegiance to one another.

As time passes, the boys grow ever closer until a horrific accident threatens to tear their friendship apart. Struggling to maintain their alliance and with the advent of war, Karl returns to Germany, while Harry joins the British Army. By a strange turn of events and with war raging across Europe, the two meet again.

Will memories of their childhood pledge prove enough to overcome their differences, or has the bond between them been broken forever?