Ben was scanning the corridor ahead of them. They were actually here. They were actually going to do this.

‘Ben,’ said Lance impatiently. ‘Which room is Father Steiner’s?’

Ben dug his hand into his pocket, and pulled out the key he’d swiped from the chaplain’s jacket the previous week. ‘The fob says Rowan. Whatever that means.’

‘They’re tree names,’ said Lance. ‘Look.’

They were passing a door labelled Blackthorn. Opposite was another marked Ash. From behind it, Ben could hear a teacher snoring. It sounded like someone sawing wood, and the noise carried so clearly, Ben was convinced it would rouse the entire floor.

Lance seemed unperturbed, and crept on.

Rowan was exactly halfway along the passageway, they discovered, as far from an escape route as it was possible for it to be.

Lance gestured for the key and, when Ben passed it over, immediately slid it into the lock. They knew the room would be empty, because Father Steiner was away for the entire week, but Ben had a sudden fear that there might be someone waiting for them inside. Isaac maybe, was his first thought, even though he’d seen Isaac asleep in his bunk as he’d crept from his dorm. But if not Isaac, then perhaps one of the teachers. Or even the headmaster himself …

For a moment Lance seemed to struggle, as though the key wouldn’t turn. It was possible that, rather than issuing Father Steiner with a spare, the caretaker had changed the lock. But then there was a click, and the sound of a bolt drawing back. Ben knew he should be pleased – he had a feeling that, if the key hadn’t worked, Lance would almost certainly have blamed him – but instead he felt his stomach fall. There was no backing out now.

‘After you,’ said Lance.

Ben’s first thought when he entered the room was that the chaplain was asleep on the bed. In addition to the shape of the bed covers, like a man lying curled up on his side, it was the smell that convinced him. He recognised it from the vestry, from all the times Father Steiner had stood close. It was a dusty, slightly unwashed musk, tinged with incense and coffee, and the chaplain carried it with him wherever he went.

But as Ben’s eyes adjusted to the gloom, he saw the bundle on the bed was just a pile of blankets. And there was enough light from the bulb in the corridor to show him the rest of the room was empty, too.

He felt a rush of relief – which vanished instantly when Lance closed the door behind them and switched on the overhead light.

‘Are you crazy?’ Ben spluttered. ‘Someone will see!’

‘Relax, would you? Everybody’s asleep.’ All business now, Lance strode past Ben, deeper into the room.