IT TOOK RUBY APPROXIMATELY TWENTY-THREE MINUTES to reach the Warrington Apartments on Avenue Walk. When she got there she found a place to hide her skateboard, behind a low stone wall to the side of the building, then looked for the easiest way to make her ascent without being spotted.

      It wasn’t exactly an easy climb and even as she hauled herself up the outside of the building, she tried not to dwell on the possible challenges to come, not least how she was going to bluff it if the security guard decided to pop into the apartment and have a check around. The wind was howling outside the Warrington, fluttering her hair, and it hampered her progress; on the other hand it meant everyone had their shades drawn and no one would hear her.

      Arriving at the thirty-seventh floor, she looked down at the teeny cars and the few tiny night-time sidewalk walkers below. The air was a little on the chilly side and she had to admit she wasn’t exactly comfortable, but nor was she fearful. She felt sort of in her element crouching there on that windowsill. She hoped it was the baby’s room she was peering into – give it a go, she thought, and she set about opening the window, using the laser-cutting device on her Escape Watch, she was in in a matter of minutes. She landed softly on carpeted floor.

      There was no doubt about it being Nileston’s room – it reeked of baby lotion and talcum powder and all that other gunk people smeared their babies with. First she headed for his cot, methodically looking in between the bedding and even under the mattress. Then she searched the floor, under the shelves, anywhere that was in baby reach, nothing above a couple of feet. After thirty-two minutes she got lucky while she was rooting through the toy hamper next to the window.

      It was underneath Mr Potatohead.

      ‘Bingo!’ she whispered, as she pulled out a slightly chewed little white card.

      Ruby made it down to the street without so much as a graze, retrieved her skateboard and began wending her way through the streets, still busy even though the hour was late. She stopped only to get her bearings, looking around to try and get a steer on the best route home. It was when she looked up northwards that she saw him.

      A tiny figure was walking across the sky.

      The skywalker.

      When the cab driver had mentioned him the other day on the way to St Angelina’s she hadn’t taken much notice, it sounded like the product of someone’s wild imagination or a film festival stunt. But now she thought, What if the window thief and the skywalker are one and the same? What if he doesn’t just climb – what if he walks a high wire too?

      She watched the little figure. He was headed towards the seedier part of downtown Twinford, away from the smart set.

       Where are you going?

      He wasn’t so far away, but as she made it further into that part of the city where the apartments became offices and the buildings became taller and denser, she began to lose sight of him. She wasn’t exactly sure but she thought he was walking the gap between the Luper Building and the Carrington Apartments, or was it the Berman Block? She managed to sneak into the main entrance of the Luper, taking the elevator as far as it went and continuing on up the stairs and out onto the roof. Now she could see clearly: the building the skywalker was headed to was neither Carrington nor Berman – it was the Hauser Ink offices.

      She could see where the high-wire cable stretched, and in theory she could follow, but the gap between the roof she stood on and the roof he was walking to might as well be a mile apart. Her balance was good and she was not afraid of heights, but she knew her physical limits. There was no way she could walk a hundred feet of steel cable.

      Ruby watched the tiny figure as he crossed the barely visible wire. He was mesmerising. It was almost like watching a dancer, so precise, so confident, and for just a moment the beauty of the spectacle became the only thing and Ruby quite forgot why she was there. She shook herself – Get a grip Rube. He had almost reached the other side. Should I follow him? This was the closest she had come to their thief – assuming of course that he and the skywalker were indeed one and the same.

      The skywalker was tantalisingly close – others had seen him stepping across clouds and air, but no one had got near to catching him. This was Ruby’s big chance. If she followed then she would be able to identify him – find out if he was their guy. If so, she could inform the Spectrum team – it wasn’t like she planned to wrestle him to the ground or anything.

      She walked over to the wire. He doesn’t know I’m here, so long as it stays that way then I am perfectly safe. She thought about that statement for a second. So long as I don’t fall, she amended. She thought about Beetle and the thrill he got from dangling from cranes and lampposts – he wouldn’t think twice, so neither would she.

      No sweat, she thought.

      She wasn’t unduly worried about the possibility of falling because her finger grip was strong and she knew that if she kept very calm and focused she would be able to grip the wire and make her way across by edging along one hand over the other. In other words she would hang on to the tightrope like some kind of monkey rather than step across it. She might be fearless but she wasn’t crazy.

      She waited until the skywalker had reached the opposite roof and then stepped onto the parapet where the high wire connected to the building. She dusted her hands in chalk and, taking the cable in both hands, slowly lowered herself down until she was hanging from the wire. Then she began to edge out across the void. She was soon dangling several hundred feet above the dark streets. It felt OK. She was confident. She would not fall. The sirens below were not reacting to her daredevil act, they were simply the unharmonious music of the city’s streets.

      She kept her focus forward just as she had been taught by coach Norov in gymnastics. Her nerves were steel and her confidence unwavering. She was a good halfway across when all that changed. She began to feel a movement in the wire.

       What was happening?

      Did it matter? Not at that exact moment. All she knew was she needed to get to the other side as fast as possible. Don’t panic but speed it up. She started moving fast, hand over hand. But it soon became clear, as the movement in the wire became more and more dramatic, that something was very wrong. The wire was going to snap. She would have to abandon it before it abandoned her.

      Otherwise you’ll hit that wall like a wrecking ball.

      She braced herself, waiting for the cable to be completely severed from its anchor, waiting for the moment when she would be swung at great speed towards the Hauser Ink Building, knowing that if she timed it right she would survive, knowing if she timed it wrong she would smash into the wall or be dashed onto the sidewalk below. No second chances; make it or die.

      Snap.

      The wire gave, and Ruby swung at alarming speed towards the Hauser Ink Building. She was planning to leap onto the large ledge just above the Hauser’s vast central window. All she had to do was time it right.

      The air rushed past. The building rushed closer.