Two more demons. But they hadn’t broken through the incursion wards in the lab. Which left only one possibility: they must have entered in the same way as the Phoenix—by walking straight through the door, riding on a human being.

Walden kept her expression very calm. The Phoenix was already alert, springing to life in her mind, its scarlet-and-gold body coiling sinuously around her forearm as it craned its head to see. There was nothing to see. Two normal-looking Year Nines. Alfie had the slight nervous stoop of a boy who wasn’t used to being tall yet. Noor had a spot on her chin, slathered in too much concealer, which was probably making it worse.

Possession.

Walden considered those chimes. One quiet, one almost inaudible. Small demons, then. But small demons should not have the strength to forcibly possess even a half-trained human magician. How could this have happened?

Well. You did the job that was in front of you, and then you got on with the next thing. Alfie first, because that had not been a very good shield—suggesting that the weakest, near-inaudible demon was riding on or inside him—and because he looked about as terrified as she had ever seen any child.

The Phoenix paid meticulous attention to Walden’s exorcism array as she drew it in tidy green chalk on the scuffed white floor around Alfie’s slowly shifting feet. Wouldn’t work on me, it said thoughtfully as Walden stood up.

I’d use something bigger for you, thought Walden, taking up a position at the northern edge of the array. Alfie shifted slowly to face her.

She got no words back, just an impression of something snapping its beak and ruffling up all its feathers. She’d hurt its feelings. Did demons have feelings?

I’m very big and complicated, said the Phoenix, with reproach and a touch of pride.

Walden knew how it felt to be exorcised—she’d done a first-year undergraduate lab practical which almost certainly hadn’t been properly risk assessed, an Oxford tradition, where her supervision group had summoned a second-order imp and then been possessed and exorcised one by one. It felt for about three and a half seconds like something was trying to squeeze your lungs out through your throat. Then it was fine; a relief, even, as the weight of demonic power lifted from your limbs. Alfie’s slowed-down cry of agony was still very hard to listen to. His mouth opened. A wisp of something dark and smoky-looking emerged. Walden’s right hand snatched it out of the air without her needing to think about it. The smoke, crushed between her fingers, left a chalky black residue. Barely big enough to eat, the Phoenix remarked.