NINE

      Hearing his name called and smelling Finn, Yo-yo ducked out of the rough-and-tumble in the ratters’ yard and ran up to the kitchens. He found the good girl among a forest of legs – Yap!

      “Good boy! Come!” said Carla.

      She took Yo-yo into the service passage, ran her fingers through her hair and deposited Finn onto Yo-yo’s head.

      Finn disappeared into his fur and made his way through to a position just behind Yo-yo’s left ear. His old pilot position. Back home, he’d been able to steer Yo-yo wherever he wanted to go. But now? After so long?

      There was only one way to find out.

      “Up, Yo-yo! Up, boy!”

       YAP!

      Finn felt the whole happy mountain of Yo-yo erupt beneath him as he jumped clean into the air.

      “Good boy! Through the door!”

      “Don’t do anything stupid!” Carla warned, as Yo-yo pushed through the swing doors back into the kitchen.

      “What’s over there, what’s on the other side?” Finn demanded, and Yo-yo yapped and ran joyously through the legs, dodging dropped pans and puddles of soup. Finn clung on happily, riding a galloping dinosaur once again, all the old feelings coming back as they broke through the far doors to hit the Forum.

      Directly opposite, Finn could see the arched entrance to the catacombs, which Olga had told them led eventually down to the Caverns.

      “Through there, Yo-yo,” ordered Finn, and the dog bounded ahead. “Come-by!” he yelled to steer the bounding dog the right way. No one noticed because no one cared about a dog. The ratters were even more invisible than the Carriers, given freedom to roam and licence to kill.

      A little beyond the archway was the catacombs door.

      “What’s in there?” Finn demanded.

      He felt Yo-yo rise as he stood on his back legs and pawed at the handle till it turned, the same as he’d done at Grandma’s house all his doggy life.

      The door swung open – and they were greeted by skulls, set into the walls like bricks, the remains of thousands of ancient monks. Yo-yo whimpered.

      “It’s all right, boy. Go on.”

      They trotted down the skull-studded passageway, claws skittering across the flagstones. Finn heard a distant hum – mechanical? – coming from somewhere beyond, and footsteps too, ahead of them. There!

      “Easy, Yo-yo,” Finn urged as they closed on the figure hurrying ahead of them. Finn remembered her as the one who’d struck Carla the blow – the Abbot’s secretary. Could she be on her way to the Caverns? Where else would she be going?

      “Follow the lady. Easy. Nice and slow,” ordered Finn.

      Yo-yo obligingly padded after her as they wound through the catacombs, keeping at a steady distance. Eventually they emerged at the top of a steep stone staircase.

      The secretary was disappearing through an archway far below and the hum was getting louder.

      “Down you go, boy.”

      When they reached the bottom, Finn saw the archway was the entrance to a tunnel into the bedrock. Three burly Siguri stood guard.

      “Lie down!” ordered Finn, so that Yo-yo would remain hidden from view. How were they supposed to get through? Wouldn’t the Siguri just kick back a dog?

      With a squeak, a solution presented itself. A few feet ahead, a brown rat emerged from a drain cover. Immediately, Yo-yo’s body twitched.

      “That’s right, boy! Chase the rat! Fast, boy!”

       YAP!

      “Hey!” one of the Siguri called in surprise, as a dog exploded out of the darkness. He raised his gun – but just as quickly one of his comrades stayed his hand.

      “Ratter! Let him do his job!”

      All three stepped aside as the rat sped forth, with Yo-yo snapping at its tail – YAP YAP YAP!