Free Mister Monday by Garth Nix

door. It was locked, but there was a release button inside a glass box, plastered with warning signs about alarms and only being used in the event of fire.
    There was a fire. Arthur swung his backpack at the box and smashed the glass. It broke into tiny clumps rather than shattering. He reached in with his left hand and punched the button, because he didn’t want to let go of the Key he held tightly in his right hand. Somehow it helped him breathe, and he really needed to breathe properly right now. He could hear the Fetchers behind him, growling and grunting as they raced along the corridors made by the shelves, pausing at each intersection of the Dewey Decimal system to sniff out his path.
    Nothing happened after he pressed the button. Arthur’s hand trembled as he punched it again. The button pressed in easily enough, but the door didn’t open. Arthur kicked the door, but it wouldn’t budge. As he kicked it again, a red flame ran around the door frame. The same rich, deep red of Noon’s fiery sword.
    “The back door, my Fetchers! Ar-tor attempts the back door!”
    Noon’s voice carried through the fire alarm, the siren, and the Fetchers’ barks. Arthur immediately knew that Noon had used his powers to seal the door. But Arthur had his own magic. Or at least he had something that had power, even if he didn’t know what it really was or how to use it.
    The Key.
    Arthur touched the door with the point of the minute hand and shouted, “Open!” There was a flash of white light, a sudden heat upon his face, then the twin leaves of the door flung open and a new alarm joined the cacophonous wail. Arthur ran out onto the fire stairs and jumped down the first two steps. Then he suddenly stopped, whirled, and jumped back. He had to close the doors behind him or the Fetchers would catch him for sure. But he had wasted a precious second—could he do it in time?
    He threw himself at the doors and slammed them shut, just as two Fetchers leaped at the gap. Arthur was thrown backwards and the doors started to open again, the Fetchers yowling and growling as they tried to grab him. Fingers ripped at his shirt, buttons went flying, but he slashed with the Key and the Fetchers let go, screaming horrible high-pitched screams.
    Arthur slammed the doors again and made a wild cut across them with the Key, shouting out, “Shut! Lock! Close!”
    Whether it was the cut or the words, the doors stayed shut, though Arthur could hear the thuds as the Fetchers threw themselves against the exit. But he didn’t hang around. Arthur knew that no doors would stop Noon.
    He’d only made it to the narrow hall between the library and the school refectory when there was an explosion above him. He crouched down and looked back as flames jetted out in all directions, and the doors flew over his head, whistling towards the science block a quarter mile away. Noon strolled out onto the fire stairs, black smoke rolling out in coils above his head, with the Fetchers crouched around him. They looked less like men now and more like half-human dogs, their black suits in rags and their bowler hats lost somewhere in the burning library.
    Arthur turned to run again. But he had only gone a few yards when he heard the whoosh and beat of giant wings above him. A cold shadow passed over his head, and Noon landed right in front of him. His wings were spread wide, his flaming sword had appeared in his hand once more, and it was pointed right at Arthur’s throat.
    “Give me the Key,” instructed Noon calmly.
    “No,” whispered Arthur. “It was given to me.”
    “It was a mistake, you foolish boy,” said Noon. He looked through a window at the sun and frowned. “Hand it over, circle end first. I haven’t got all day.”
    Something about the frown and the way he said those last words sparked an idea in Arthur’s mind. He looked down, pretending that he was thinking about handing over the Key. But he was actually looking at his watch. It was one minute short of