'I'm going to live in that house, Dad. One day I'll be mistress of Thornsby Manor . . .'

It is 1910 in the Lincolnshire Wolds. Young Rosie Waterhouse lives with her father, Sam, well known as the local poacher, in a cottage on the Thornsby estate. The land is owned by William Ramsey, a harsh and heartless man who is determined his only son, Byron, should marry well and produce an heir.

Rosie is quick to learn the tricks of her father's trade and it's when she's poaching fish from the estate's stream that she meets Byron. They continue to meet in secret over the coming months and, as their friendship blossoms, they recognize that, despite their vastly different backgrounds, they are destined to be together. When William learns of their bond, he stops at nothing to ensure that they never meet again.

As the years pass and the threat of war becomes a reality, Sam is involved in a tragic incident that will affect both his and Rosie's lives more than they could ever have imagined. Life will never be the same in Thornsby, but will Rosie find the happiness she yearns for?