Dawnlands (The Fairmile #3)
Philippa Gregory

Alinor’s son, Rob, is determined to stay clear of the war, but when he and his nephew set out to free Ned from execution for treason and Rowan from a convict deportation to Barbados, they find themselves enmeshed in the creation of an imposter Prince of Wales—a surrogate baby to the queen.
From the last battle in the desolate Somerset Levels to the hidden caves on the slave island of Barbados, this third volume of an epic story follows a family from one end of the empire to another, to find a new dawn in a world which is opening up before them with greater rewards and dangers than ever before.