Once Charlie had surrendered, he’d sprinted back to the CVS, then jogged a mile and a bit down South Rainbow, until he came to a little outdoor mall. It had the usual suspects: Starbucks, Burger King, Kurt’s Sporting Goods and Dollar Dominator. He’d been here twice with his aunt and knew he’d find men’s toilets by the kids’ play area.

Stupid American toilets, Harry thought, seeing a row of aluminium partitions that started ten inches from the floor and stopped below head height. But nobody’s in here and it’s pretty clean …

He bolted a stall at the far end, went down on one dirty knee and opened his backpack. The Nikon was Harry’s most prized possession, but he’d shoved it in the bag without the lens cap, and it felt horrible seeing it covered in dust, fingerprints and blood from his grazed hands.

But camera cleaning came way down the list. He unrolled Charlie’s jogging top, brushing his hand on the gun as he pulled out the plastic-wrapped brick. It had an oily, metallic smell, even though Charlie had sealed it in a heavy-gauge rubble sack wound with several yards of duct tape. Harry tried getting inside with his nail, but he only got a couple of tiny strips off before realising it would take forever.

He needed something sharp. His first thought was a key. He’d carried several back in London, but out here the Sinatra’s apartments opened with a plastic fob, he had no bicycle to lock and Rock Spring High lockers had combination dials.

Luckily, Harry had left home in a rush. He’d pulled all the schoolbooks out of his pack, but a bunch of pens and his geometry set still rattled at the bottom. The compass point speared the plastic, releasing a burst of the heavy oil smell. He stabbed and gouged until the explosive brick was fully exposed.

The outer layer had dried to a bluish-green crust, with dozens of dead bugs stuck to it. But when Harry dug in – using his protractor as a scoop – the inside was gooey, like the little French cheeses his aunt liked.

He let a chunk plop into the toilet and flushed, not relishing the idea of having to fish it out if it didn’t go down. But it went down fine and he flushed two more lumps, before realising that the swirling water had drowned out the sound of his phone ringing.

‘You’re having a great day, young fella!’ Ellie Gold said cheerfully as soon as he picked up.

‘Am I?’ Harry said, unconvinced, as he kneeled in front of the toilet, looking at a slab of explosive that could level a house.

‘Do you want the good news or the great news?’

‘Whichever,’ Harry said, straining not to be rude, but desperate to flush the explosive and get out of the restroom.