And then, since Kenning didn’t seem inclined to move, she cast a modified wind spell to give her a little shove out of the door, and sent Will floating through alongside her. She had just enough time to let the levitation down gently before the strain of holding the portal open grew to be too much. Walden felt the sting of magical backlash when it snapped shut, as if something had just tried to close needle-sharp teeth on her fingertips.

Then she was alone in School House, alone in a critical demonic incursion. She could no longer make out the lines of the front hall—the coat hooks, the family pictures, the bicycle—through the fog of wild magic. The doorframe behind her stood alone in an expanse of shadow that was punctuated only by a boreal shimmer of shifting purple light.

No sign of Old Faithful yet. That was not a hopeful thought. Walden knew it was here; and if it was not paying attention to her, then it was paying attention to something else.

Nikki and Mathias were in the tower. They were still alive. Walden chose to believe this because the alternative was unbearable.

She turned away from the door and headed in.

chapter eight INCURSION

Invocation was Walden’s magical specialty and her life’s great passion. She was an expert in creating tiny and tightly contained demonic incursions, overlaps between the mundane and demonic planes, in order to conduct her carefully managed trade: pieces of mundane existence, which could be as small as the vibrations in the air she breathed, in exchange for a demon’s effortless facility with magic, the stuff that was as natural and intrinsic to their existence as water to fish. Incursions were by nature unstable and temporary. A single incursion ought to be just big enough to allow one demon of predictable size to travel from one plane to the other for a very short period of time, without gaining any foothold in material existence beyond a temporary reification. But ‘ought’ was doing a lot of work in that sentence; ‘ought’ was about expert practice and effective risk management. The truth was that there were ways to make bigger incursions, and to have them last longer. These were mostly very expensive in raw materials, beyond the reach of any individual magician who was not personally a billionaire—and also, of course, insanely dangerous and highly regulated. But Walden had seen one such mega-incursion, created under controlled conditions in a lab in the Arizona desert, which had been going for nearly forty years.