In May 1914, as war looms in Europe, the Japanese steamer Komagata Maru arrives in Vancouver harbour, carrying 376 would-be immigrants of East Indian origin. As subjects of the British empire, all are entitled to enter Canada, but the authorities refuse to let them ashore.

While using every means at his disposal to enforce the racist policies of his political masters, immigration inspector William Hopkinson is torn between his own ambition and the secret he harbours within.