Thirteenth-century Wales is a divided country, ever at the mercy of England's ruthless, power-hungry King John. Llewelyn, Prince of North Wales, secures an uneasy truce by marrying the English king's beloved illegitimate daughter, Joanna, who slowly grows to love her charismatic and courageous husband.

But as John's attentions turn again and again to subduing Wales – and Llewelyn – Joanna must decide where her love and loyalties truly lie.