Ben's in danger of spending his holidays cooped up in a caravan with his mad Aunt Gwen. But by luck (and bribery), he gets a place on the school trip to an outward-bound centre in Wales, along with Barney, Jenks and of course, Agent Z. Abseiling, orienteering, sinking enemy canoes and sabotaging toothpaste are all in a day's work for the Crane Grove Crew. But then they uncover a news clipping which reveals that their centre manager, the affectionately nicknamed 'Grenade-head', is in fact an escaped bank robber. He's planning to recover the buried loot any night now and Agent Z and the crew intend to be there when he does. If you think that sounds like a downright ridiculous plan, you'd be right. Especially as the escaped criminal story turns out to be the invention of the crew's new pal, Roz and for once, the joke's on them! Mark Haddon has a sharp understanding of what makes children tick, and they will delight in the ever more daring, ever more hilarious missions of Agent Z and his three creators.