Set in Bristol in 1916, in a world plunged into war, Conkers and Grenades follows Mar and Appy, two boys who discover a spy ring and a plot to assassinate the king and queen. Whilst trying to 'do their bit' for the war effort, Mar and Appy unwittingly become entangled in a web of secret agents, codes and danger. People are not quite what they seem; they find friendship but also betrayal. Dragged into the world of spies and intrigue by the most unlikely person, they risk their lives but think that like their dads, who are fighting in France, they should also do their best to help. As well as coping with the spies, they have to put up with issues at home – there's never enough to eat and there's always the possibility that friends and relations, fighting at the front, will go missing in action. They also have to try to earn money to put extra food on the table for their families. Pitted against expert (and much older) adversaries, do Appy and Mar really stand a chance of coming out victorious? And in such an uncertain world, who can they really trust..?