The Mask of Destiny by Richard Newsome

you’re wrong, genius.’
    A rumble sounded from above and another surge of water shot though the cave opening. It hit them like a bomb, pushing them beneath the surface.
    â€˜Right,’ said Sam when they came up for air. ‘We’re going to have to do a little more swimming.’
    â€˜Swimming?’ Ruby said. ‘Where?’
    â€˜It’s not far,’ Sam said. ‘Trust me.’
    The look on Ruby’s face made it clear trusting Sam was the last thing she was going to do.
    Sam led Ruby to the middle of the pool, up to her armpits. ‘Just take a big breath and follow me, okay?’
    â€˜What if I run out of air?’ Ruby said, staring horrified at the surface.
    Sam thought for a second. ‘That would be a bad thing.’
    Before she could give it any more thought, Sam grabbed her hand and they both disappeared beneath the water.
    Gerald glanced up at the sound of another wave approaching. An avalanche of water was rushing down at him. He took a breath, and dived.
    Gerald was vaguely aware of the surface above him being bombarded by the pounding waters flowing in from the bay. But his senses were focused on the shaft of torchlight that probed the darkness ahead of him. He kicked down. He could just make out the two fingers of light coming from Sam and Ruby’s torches below. They were tracing the edge of a sheer rock shelf, deeper and deeper into the pool. Gerald’s ears howled in protest as the pressure ground into them, squeezing like a clamp on his head.
    Then he lost sight of the others.
    His torch sliced into the gloom but all he could see was rock wall plunging ever deeper. There was no sign of Sam or Ruby. They’d gone.
    Gerald kicked on, driving himself deeper. And then the rock shelf disappeared. All he could see was bottomless space. His lungs tightened; he was running out of air. Panic rose in his gut. What was going on? His friends had vanished. He had a head-spinning sense of disorientation. Which way was up?
    Then Gerald thought to blow out a bubble. His eyes followed its smooth ascent. And his sense of place was restored. He had swum under the rock shelf. He turned his head for the surface and kicked hard. Just when he thought his lungs would collapse, he burst into the sweet salt air.
    Sam and Ruby were sitting on a sandy bank at the edge of the pool. Gerald crawled out of the water and flopped beside them. They were in a vast grotto. The ceiling soared high above, lost in the stalactites and shadows.
    â€˜We should be safe from any high tide in here,’ Sam said, his voice echoing into the space around them.
    â€˜Won’t this just fill up like the other cave?’ Ruby asked.
    â€˜I reckon that rock shelf we swam under is a bit like an S-bend in a toilet,’ Sam said. ‘The water level will get as high as the other cave, but this one goes higher up into the island, so we can climb above the tide.’
    Gerald let out an empty laugh. ‘We’re in a toilet? Seems about right for how I feel at the moment.’
    He adjusted his headlamp. Their little beach opened up to an enormous cavern. A rocky platform rose gently behind them.
    â€˜Let’s see where this goes,’ Gerald said, and he clambered up onto the platform.
    Ruby swept her torch in a broad arc, catching details of crags and fissures in the walls of the stone cathedral around them. ‘I wonder if anyone has ever been down here,’ she said. She glanced across at her brother. ‘Hope there aren’t any rats.’
    Sam’s jaw tightened. ‘There’s no need for that,’ he said.
    â€˜You’re being very brave,’ Ruby said. She skipped ahead to catch up with Gerald. ‘I’m very proud of—’ This time, Ruby’s scream almost ruptured Gerald’s right eardrum.
    â€˜What is it?’ Sam raced to join them. Ruby was clamped onto Gerald’s back like a petrified koala. Three beams of light converged on a