In the thirty-first Discworld novel the Discworld goes to war. Trousers. That's the secret...Put on trousers and the world changes. We walk different. We act different. I see these girls and I think: idiots! Get yourself some trousers! Women belong in the kitchen - everyone knows that. Not in jobs, pubs or indeed trousers, and certainly not on the front line. Nonetheless, Polly Perks has to become a boy in a hurry if she wants to find her missing brother in the army. Cutting off her hair and wearing the trousers is easy. Learning to fart and belch in public and walk like an ape takes more time. There’s a war on. There's always a war on, and Polly and her fellow raw recruits are suddenly in the thick of it. All they have on their side is the most artful sergeant in the army and a vampire with a lust for coffee. It's time to make a stand.