"Heirs of Promise', the second part in the gripping Z-Rod trilogy set in 6th century Scotland, intriguingly contrasts the lives of Pictish cousins striving to establish themselves - one as warlord, the other as a spiritual warrior. Styling himself on the boar, Oengus uses power and wily intelligence in a bid for independence from his overlord under the gathering gloom of war. Other shadows disturb: his ousted cousin, who bears the powerful 'Z-rod',...