“For cog’s sake, that thievin’ gub!”

Scrap stamped his foot so hard it rattled. As the billboard floated away under the bridge, he began spitting out expletives that Gnat was sure were so rude that she would never be allowed to say them.

“What is it? What’s the matter?” Paige asked.

“He took it … he -zk- took it!” barked Scrap. “The Strongbox … I’ve got to get to the Strongbox…”

“The Strongbox?” Paige replied in an urgent whisper. “You just said we should stay out of sight and—”

“Change of plan!” Scrap interrupted. “Just -zk- stay here! I -zk- I’ll come back for you…”

With that, he started making his way alongside the river as fast as Paige and Gnat had seen him move.

“But we want to stay with you!” Gnat shouted after him. “We want to stay with you, Scrap!”

Paige looked at Gnat, Gnat looked at Paige, in their sanctuary of shadows under the bridge.

Then, without saying a word, they replaced their helmets, and raced after Scrap.

The sisters had a hard time keeping up with the diminutive, one-footed robot as he made his way through the city. He limped with a determination they’d not seen before, even when they were fleeing for their lives. The streets were narrow, with uneven, cube-built buildings rising up on both sides, and an increasing number of robots wandering here and there. Paige and Gnat ducked under legs, between wheels and around robots of every conceivable shape, size and design. Every minute or so, Scrap would stop to look up and, sure enough, a floating billboard or bright neon arrow would point in the direction of the Strongbox, accompanied by a countdown:

Each direction only made Scrap redouble his efforts to reach his destination, and made keeping up with him even harder.

A clamour of noise announced the Strongbox long before Scrap saw the huge cube, looming at the end of a busy, narrow street. The building seemed to be half buried, as red light emanated from an open doorway leading underground. Paige and Gnat were still fifty paces from Scrap when they saw him pushing past larger, finer robots with redoubled resolve, before hurrying through the doorway and disappearing inside.

Paige squeezed her sister’s hand tightly, nerves and common sense getting the better of her. She looked down at her core tracer, its tiny screen confirming what she already knew – the Strongbox was teeming with robot life.

Turn back, she told herself, but with a river of jostling robots behind them, neither she nor Gnat had any chance of turning back or even slowing down. They were all but carried towards the glowing doorway and into the subterranean arena.

The noise hit them first. More noise than they had ever heard – robot chatter echoed around the cube. What struck them next was a wall of heat and thick, metallic-tasting air. A long, wide ramp lead to another cube, standing in the centre of the room. Metal rods jutted vertically from each corner, with cables strung from one to the other. Paige already knew what this was – a fighting arena. A dozen or so hovering video-drones buzzed around it, waiting for the bout to begin, eager to record every moment.

As the last of the robots took their seats, Paige spotted a rotund, gaudily coloured robot hovering in the air several metres above the floor of the arena, its voice echoing to every corner of the Strongbox.

“Mayor Highshine is proud to celebrate our rich cultural traditions through the time-honoured enjoyment of ritual skirmish! ’Bot versus ’bot! Power-driven prize fighters, proudly punching their way to victory and upgrades! I’m your host, Cal Cutter, and this is the night you’ve been waiting for … this is ’Bot Bouts, Round 15!”

“UFff…!” Paige grunted as a passing robot bumped into her, knocking her on to the ramp.

“In Rock ’Em corner,” Cal Cutter continued, “weighing in at 711 kilos … he may be chatty, but his actions speak louder than words, it’s Victor Da Spoils!”

The roar grew louder as a huge, egg-shaped robot with long, broad arms clambered into the ring.

“Where’s Scrap?” asked Gnat. “I can’t see Scrap…”

“In Sock ’Em corner, weighing in at 855 kilos … don’t be fooled ’cause he’s old-school! He’s the never-in-doubt King of the Bouts, it’s Morten Prometheus!”

Another roar. The blue and grey titan that stepped into the ring was by far the biggest robot in the building – two and a half metres of metal brawn. His entire body was covered in numerous scratches, dings and dents, which didn’t seem to bother the metal giant one jot. A deep blue cape cascaded down his back, decorated with a bright star field – a map of some unknown galaxy.

“One winner! No time limit! Knock out or tap out!” The announcer bellowed. “Seconds out, round one!”

Without pause, Morten Prometheus thumped his opponent so hard that Victor Da Spoils was lifted off his feet. He collided with the taut metal ropes and fell backwards out of the arena, crashing to the ground inches from the front row of spectators.

“Morten Prometheus comes out swinging! Victor Da Spoils is down and out of the arena!” boomed the announcer. “Looks like it’s going to be another good day for the champion of the ’Bot Bouts!”

“Hey!”

The cry was barely loud enough to register over the din, but Paige recognized the voice. She paused, and turned.

Another robot was climbing into the arena.

It was Scrap.