Midnight City by J. Barton Mitchell

Focuser and reflect the air Essence. At the other end, she placed the second coin, also heads facing out (which would make the polarity of the artifact combination “positive”).
    When she was done, she wrapped the items together with the duct tape. As the Interfusion was made, the hair on Mira’s arms stood up. A slight charge sparked the air, and there was a crackling, a hum. Like something electrical was charging up. Mira opened the glass vial peeking out from under the tape. A hiss of air, a shimmer, the hum intensified for a second … and then everything went silent.
    At the same time, Mira’s hand … vanished.
    She dropped the artifact. Her hand reappeared, and a small rock that the artifact landed on disappeared in its place.
    Zoey stared in wonder. “How did you do that?” she whispered. “Can you do it again?”
    Mira smiled, put a finger to her lips. The artifact combination created pure invisibility by reflecting air and light away from whatever it touched. Impressive … but not enough. Not yet. She needed to make a second combination, using the first as the new Essence.
    From her pack, she pulled out more items: two dimes (also wrapped in plastic) and a large blue green marble.
    Mira started with the coin (heads out). Next was the artifact combination she had just made, and then finally the marble and the second dime (again, heads out). She wrapped it all together with duct tape.
    As she did, the hum came again, but this time it was louder. The air shimmered and blurred as a cocoon of invisibility enveloped her. Everything on the outside was muted and darker, like looking at the world through sunglasses.
    This combination was an often-used one, called a Shroud. It incorporated the first artifact combination, increased its power, and forced the invisibility to flare outward in the form of a sphere (thanks to the marble Focuser). Now, whoever held it was surrounded by a ball of invisibility. At least until the combination’s power ran out, which wouldn’t be long from now.
    Mira studied the artifact combination with distaste.
    She prided herself on not just the ingenuity of the artifacts she created, but also their aesthetic virtues. Since leaving Midnight City, it seemed she was always making combinations in a frenzy. She didn’t have the luxury to take her time anymore, to use pretty bindings like gold or silver chain, lengths of silk of varying hues, or even colored twine. Now her artifacts were hastily created lumps of duct tape or rubber bands, without form or color or artistry.
    It was one more thing she had lost when she fled.
    “Stay here,” Mira whispered to Zoey. “I’m going into the camp.”
    “I can’t pet the Max?” Zoey asked dejectedly.
    “No, sweetheart, not right now. I need you to stay down and out of sight. Okay?”
    Zoey pouted, but made no move to follow Mira as she crawled slowly forward.
    Mira advanced cautiously. Though the Shroud kept her invisible, it didn’t make her intangible. She would still make noise and disturb the brush, which could give her position away. She had to be patient, take her time.
    Mira inched into the camp’s interior, studying the layout as she did.
    Holt’s pack lay at the far end, resting against a collection of trees that had grown upward together and intertwined. It was isolated and apart from the rest. Mira frowned at Holt’s obviousness: it was clearly where he meant her to go. It was where the trap would be sprung … whatever it was.
    She surveyed the rest of the camp, and her eyes found Holt’s cot. The sleeping bag on top looked full, the blankets pulled up tight around the supposed occupant. Mira almost laughed out loud, wondering if it had taken every piece of extra clothing Holt had to make it look like someone was inside the bag.
    What kind of fool did he take her for?
    There was no sign of Max either, which meant the dog was probably with his boss, waiting on her to make a grab for Holt’s pack at the other end of the