AT 2.30AM RUBY GOT OUT OF BED, pulled on her jeans, a T-shirt printed with the words excuse me while I yawn and a sweater, picked up her sneakers, pushed open the window and climbed down the eucalyptus tree. Its limbs stretched towards the west side of the house providing a perfect ladder for the able tree-climber.

      Hitch was already sitting in the silver convertible, its engine turning over so quietly you hardly knew it was running.

      ‘Nice of you to show up,’ he said.

      Ruby looked at her watch. It was 2.32am. ‘Give me a break,’ she said.

      ‘Lives have been lost in two minutes,’ said Hitch.

      ‘Oh, come on man, what’s the big deal?’

      ‘The “big deal”?’ pondered Hitch. ‘Let me think… well, I hear you can only breath-hold for one minute and one second so imagine if you were waiting for me to rescue you, and you were stuck underwater, and I took a whole two minutes to get there. You’d be all out of air kid.’

      ‘You were waiting in the car. You weren’t exactly in total mortal danger.’

      ‘You didn’t know that.’

      ‘OK, OK,’ said Ruby. ‘I’m sorry, I won’t do it again.’

      ‘I wouldn’t bet on it,’ said Hitch. ‘Listening to advice isn’t what you do best.’

      ‘Well, since we are busy “sharing” here then might I suggest that giving people the benefit of the doubt isn’t one of your strengths?’

      Hitch pointed at Ruby’s T-shirt and said, ‘Your T-shirt is on the money kid, so zip it.’

      He backed out of the driveway and they drove in silence to Desolate Cove. As the name sort of suggested, no one much visited this place – it had no sand and was nearly always windswept and rarely warm. Hitch parked behind a steep bank of pines, the vehicle hidden from view, and he and Ruby set about zipping their jackets and pulling on rubber waders. In silence they walked across the pebble beach until they reached the place where the cliffs met the water.

      ‘Stay close to the rock kid,’ warned Hitch. ‘There’s a sudden drop to the left – very deep water and I’m not sure I can be bothered to fish you out.’ The sound of his words was almost drowned by the sound of the sea as it dragged through the stones of the beach, relentlessly pulling and pushing, almost like a chorus of whispering voices.

      Here you could perhaps believe in the fisherman’s legend of the sea devil and the sea witch.

      The water reached almost to the top of Ruby’s waders and she just barely managed to keep from getting soaked. She had no idea where they were headed or why, but she guessed there must be a pretty good reason for this little jaunt.

      They made it round the next sharp corner and then there it was: a hidden low opening in the cliff, not so much a cave, more like a large niche, just big enough to conceal…

      … a scuba sub.

      ‘Kinda cool,’ said Ruby.

      ‘You have no idea,’ said Hitch.

      A metallic pod-like thing, the sub had a reflective glass dome on top.

      ‘The glass is four inches thick,’ said Hitch. ‘Allows the sub to dive to depths of five miles. When submerged, the light bounces off it in such a way that it is just about invisible.’

      ‘Even cooler,’ said Ruby casually, like she’d seen a whole bunch of scuba subs in her time.

      Hitch raised his eyes heavenwards and depressed a button on his watch and the glass lid slid back. There looked to be enough space to seat three passengers comfortably and four at a squeeze. It looked worryingly unstable and Ruby was concerned that it would tip as she climbed in.

      ‘Plenty of agents bigger than you have found themselves jumping into this thing, trying to make a fast getaway,’ said Hitch. ‘And I can assure you kid, it never rolls over… so long as you don’t slip, you won’t drown. If you do, it’s anyone’s guess.’

      Ruby gave him a sideways look, then climbed in very carefully and buckled up. Hitch took a key from a well-concealed compartment, slotted it into the ignition, turned it this way, that way, another way and then the engine began to purr.

      After fiddling with some switches, and once the roof was locked into place, Hitch pushed a lever and they moved forward, dipping smoothly under the waves. The cliff ledge suddenly disappeared and the sub moved into deep water.

      ‘Keep your safety belt fastened!’ said Hitch, as he pulled on another of the controls and the scuba sub suddenly jetted forward at great speed, silently cutting through the ocean. Things on either side of them vanished into a blur as they passed by.

      ‘How do you avoid colliding with a whale?’ asked Ruby, who was sort of pinned to her seat, enjoying the ride, but not yet entirely relaxed.

      ‘Automatic Avoidance Sonar,’ said Hitch. ‘I’ve never hit anything yet kiddo!’

      It was a thrill to travel so fast – better than any amusement park – but Ruby wouldn’t have minded slowing it down a little, taking some time to look at the scenery. In the blink of an eye they reached another rock face; this one seemed to be covered in petrified insects – sort of prehistoric-looking flies and insect fossils.

      ‘We’re stopping here?’ asked Ruby.

      ‘Not exactly,’ said Hitch, pressing one of the buttons on the control panel.

      What looked like solid rock suddenly corkscrewed open and they entered a water-filled channel.

      They navigated their way up the passage until they reached a dead end, a round pool. Hitch switched off the engine and a platform under the sub lifted them and their vehicle