Sheena grabbed my arm and squeezed it tightly. “Billy … we’re surrounded. The pirates … they’re alive! They’re BREAKING IN!”

  BAM. BAM. BAM.

  “Don’t you see? We woke them up!” I cried. “We woke up the pirates!”

  “Billy, they’re going to break the glass!” Sheena wailed.

  Panic swept over me. My heart pounded as loudly as the skulls on the glass. I couldn’t think straight.

  BAM. BAM.

  I slapped wildly at the ignition button.

  “It won’t go, Sheena!” I cried. “It won’t go!”

  BAM. BAM. BAM.

  The ugly skulls battered the glass.

  Sheena’s eyes were wild. Her face turned bright red. She pounded the control panel with both fists —

  — and the engine rumbled to life!

  “YESSSSS!” I cried. I shoved the stick all the way up.

  BAM. BAM. BAM.

  All around us, the skulls beat in a steady rhythm against the portholes.

  I could feel the sub start to rise. The skulls jerked back. Bony hands scratched against the glass, then fell away.

  “YESSSS!”

  The skeletal pirates disappeared beneath us. Their animal moans followed us, then slowly faded from our ears.

  The dark green water bubbled as the sub shot up. I held the stick in my trembling hand, pulled it as far up as it would go.

  “We got away,” Sheena said. “We’re heading to the surface. I knew we would. I knew we’d be okay.”

  Despite my fear, I burst out laughing. It sure didn’t take long for Sheena to get her old personality back!

  But now the frightening questions whirred through my brain once again….

  Can we find our way back to the Cassandra? If we do, will we be able to radio for help?

  Where is Dr. D? Did he really vanish from this tiny sub? How can we find him?

  Did we really see dead pirates come to life? Will they come after us? How much oxygen do we have left?

  Sheena and I stared through the porthole as if hypnotized. We watched the swirling water and didn’t say a word.

  Finally, two hours later, the Deep Diver bobbed to the surface. I blinked in the bright sunlight. The waves shimmered as we rocked gently on top of the water.

  “We made it!” I cried, letting out a long breath.

  Sheena peered out the porthole. “But where is the Cassandra?” she asked.

  I felt all my muscles tighten. “We can find it,” I said. “We didn’t go far.”

  I grabbed the wheel and began to turn the sub slowly. I made the sub spin in a wide circle.

  No sign of the sea lab.

  “It has to be here,” Sheena murmured. “It’s … our only chance.”

  Ignoring my fear, I moved the sub in larger and larger circles. But no. Nothing but ocean. Endless ocean, as far as we could see.

  We rocked on the water. The only sound now was the wash of the waves against the sub. We both stared out at the rolling waves. We didn’t say a word.

  Finally, I turned to my sister. “We’re all alone,” I said softly. “Dr. D is gone. And no one knows we’re out here.”

  Sheena frowned at me. “And what’s the good news?”

  There was none.

  Sheena jumped up from her seat and stumbled to the back of the sub. “I’m opening the hatch,” she said. She was already halfway up the ladder. “We can see better up there.”

  “Are … are you sure it’s a good idea?” I called.

  Too late. I heard the hatch lid pop. The sea sounds grew louder.

  Sheena hoisted herself to the top. The sub rocked and bobbed. The wind roared.

  “Can you see the Cassandra?” I shouted.

  She didn’t answer. I don’t think she could hear me.

  Finally, she lowered herself one rung and bent her head toward me. To my surprise, she had a smile on her face.

  “An island!” she cried. “Billy, there’s an island out there.”

  “How close?” I shouted. “Can we swim to it?”

  “We have to!” she cried. “The ocean is calm. We can make it if we take our time.”

  We should have worn our swimsuits, I thought. We were in jeans and T-shirts. But, of course, we didn’t know we’d have to leave the sub.

  A large fish slid past the porthole.

  I imagined a school of killer sharks circling us, snapping their jaws hungrily. I pictured the zombie pirates rising up from the ocean bottom and grabbing us.

  No, Billy. Don’t think about sharks — or zombies.

  I heard a splash. I turned and gazed up at the empty hatch. Sheena was already in the water.

  “Courage,” I whispered. That’s the official slogan of the Undersea Mutant.

  I searched the control panel. I found a lever marked ANCHOR. I pulled the lever down and heard a loud buzz. Some kind of electric anchor. At least the sub would be here, ready for our return.

  I pulled myself up to the top of the hatch. Shielding my eyes with one hand, I squinted into the distance. Yes. A long yellow sand island. I could see some trees near the shore.

  “Come on, Billy — jump!” Sheena called. She floated on her back alongside the sub.

  “Coming!” I shouted. I tried to steady myself over the edge of the hatch. But my legs trembled so hard, I could barely stand.

  “Jump!” Sheena yelled. “What are you waiting for?”

  “Okay, okay,” I muttered. I took a deep breath, raised both arms above my head —

  — and leaped.

  “OWWWWWWW!”

  I screamed as I hit the hatch lid. My leg scraped along the metal edge. Sharp pain shot up my left side.

  I did a hard belly flop into the water.

  The cold rushed over me. My leg throbbed with pain.

  Splashing wildly, I raised my head. I grabbed the aching leg.

  “Sheena — ” I called. A wave washed over me. I shook it off and pulled myself up.

  “Sheena — help me! I can’t swim! I think I BROKE my leg!”

  Sheena quickly swam over to me. “What happened?”

  “I … banged my leg on the hatch,” I moaned, ducking under a high wave. “It’s the same leg that shark bit last summer. It really hurts. I think maybe —”

  “Let me see,” Sheena said. She grabbed the leg and twisted it.

  “HEY! STOP!” I screamed.

  “It bends at the knee,” she said. “It’s not broken.”

  “Since when are you an expert on legs?” I cried.

  But she didn’t hear me. She was already swimming toward the island with slow, steady strokes.

  I had no choice. I had to swim after her.

  I ignored the pain, lowered my head to the water, and began doing my famous breaststroke. “Courage,” I whispered again. Just a reminder to myself.

  The water was cold, and the waves were pulling against us. I’m a good swimmer. But halfway to the island, my arms started to ache.

  My cut leg throbbed. I sucked in breath after breath and forced myself through the strong current.

  I don’t know how long it took to reach the island. Maybe half an hour. It seemed a lot longer.

  I fell onto the sandy shore, shivering, gasping for air. My chest felt ready to explode.

  I lay on my stomach, my head resting on the soft sand, breathing … just breathing. When I finally looked up, I saw Sheena leaning against the curved trunk of a palm tree, in a thick clump of ferns.

  With a groan, I pulled myself to my feet. My waterlogged jeans and T-shirt hung heavily against my body. I took a step — and let out a cry. “Ow. My leg —”

  I raised the knee and tested the leg a few times. It moved okay, but it hurt each time I bent it. I limped a few feet toward my sister, groaning with each step.

  “Here,” Sheena said. “This just washed ashore. Maybe you can lean on it. You know. Use it as a cane.”

  She held up a long stick. I hobbled over to her and grabbed it. It was a long piece of bleached d
riftwood. The perfect size.

  “Don’t call it a cane,” I told her. “It’s the Mutant’s Golden Staff of Invincibility. It was handed down to me by The Eternals.”

  She rolled her eyes. “Whatever.”

  I tried the driftwood cane out. Leaning on it, I could get around pretty good.

  I glanced around the island. A narrow strip of yellow sand formed the beach. Beyond the beach, I saw clumps of tall grass and ferns. A thick cluster of palm trees hid the rest of the land from view.

  Strange, I thought. No seagulls on the shore. No birds chirping in the trees. What a weird, dead silence.

  “Come on. Let’s explore.” Sheena’s voice cut into my creepy thoughts. “Billy, can you walk?”

  “No problem,” I said. Leaning on the cane, I followed her along the shoreline.

  Our sandals crunched on the soft sand. We passed a wide patch of tall grass blowing one way, then the other.

  “Oh, wow.” Sheena stopped and raised her arm to block me. “I don’t believe it!” she cried. She stared wide-eyed at the sand.

  I followed her gaze. And gasped. “Footprints!”

  They led from the water, across the sand, into the trees.

  “Dr. D!” I cried. “He … he made it to shore!”

  Without another word, we began following the footprints. Sheena trotted over the sand. I limped after her as fast as I could, leaning on the driftwood stick.

  The footprints led along a narrow path that twisted through a thick grove of palm trees. Tall reeds and ropy vines lined both sides of the path. We had to step over fat gray roots that poked up like giant snakes from the sand.

  I stopped to rest my leg for a moment. “Dr. D!” I shouted, cupping my hands around my mouth. “Uncle George? Can you hear me? Are you here?”

  No answer.

  My eyes on the footprints, I trotted after Sheena. “Hey!” I let out a sharp cry — and stopped beside her.

  We both stared through an opening between lush fern leaves. Stared at a man in a long black cloak with a hood pulled over his head.

  Was it Dr. D? It had to be.

  “Dr. D! It’s us!” Sheena cried.

  Why didn’t he turn around?

  I pushed the fern leaves out of the way with the stick. Then we both burst through, running over the sand to our uncle.

  “Oh!” I gasped, and stopped short.

  Sheena grabbed my arm.

  And we both opened our mouths in screams of horror.

  The stick fell from my hand. I grabbed it back and raised it in front of me. Could I use it to defend myself?

  I didn’t need it. The hooded figure in front of us wasn’t going to attack. It leaned against a tree. Unmoving. A skeleton!

  I let out a groan. “Ohhhhh, sick!” The long cloak was covered in crawling worms and insects. Bugs climbed in and out of the skeleton’s toothless mouth.

  Under the cloak, I saw a rotting shirt. On the shirt’s pocket, I saw a red skull and crossbones.

  “A pirate!” I whispered.

  “But … it’s impossible,” Sheena said in a whisper. “These footprints … Billy, look at them. They’re fresh!”

  I glanced down at the sand. Yes. Fresh footprints. Still deep in the sand.

  “No. No way …” I murmured. I watched the fat brown worms slither around the grinning skull.

  A chill made my whole body shake. I couldn’t take my eyes off that ugly face.

  “Billy, didn’t you hear me? Let’s go!” Sheena shouted.

  I shook my head hard, trying to clear my mind. Trying to shake away my panic.

  Sheena grabbed my hand and pulled me along a twisting path. We hurried through the trees and vines back to the beach. I struggled to keep up with her, leaning on the stick.

  The sun was now a red ball, low over the water. The late afternoon light turned the ocean red and purple.

  A pretty sight. But there was no way we could enjoy it.

  “Stranded on a tiny island with a disgusting dead pirate,” I muttered. “Dr. D is gone. And we have no way to get home. Could it get any worse than this?”

  “Yes, it could,” Sheena replied in a whisper. “I think it just did.” And she pointed to the sand in front of us.

  I held my breath and followed her gaze. “Oh, no!” I saw at least a dozen sets of fresh footprints in the sand.

  “They all lead from the water,” Sheena said softly. “They cross the beach and go into the trees.”

  “They are skeleton footprints,” I said. “See? Bone prints.”

  We stared at them, then at each other.

  “The dead pirates!” Sheena cried. “It must be them. The pirates who smashed their heads and fists on the sub.”

  She shuddered. “We woke them up, Billy. Don’t you see? When we crashed into their ship, we woke them up. And now they … they followed us here!”

  My mind spun. “We … we have to find a hiding place,” I said. “Somewhere safe where we can try to think.”

  “Away from this beach,” Sheena said. “Away from these footprints.”

  I stared at the bony footprints pressed into the sand. Once again, my imagination took off.

  I pictured the dead pirates staggering out of the waves. I could see them shaking water off their rotted clothes. Walking stiffly on the sand, their bones creaking and cracking and grinding.

  Searching blindly for Sheena and me.

  We trotted over the sand. My leg felt better. But I used the long driftwood stick to help pull myself along.

  “Sheena, look!” I pointed to a tall pile of gray rocks at the far end of the beach. “There might be caves,” I said. “Or a good hiding place behind the rocks.”

  “Let’s check it out,” Sheena said.

  We took two or three steps.

  “Whoooooaaaa!” I let out a startled cry as the sand gave way beneath me.

  My arms shot up in the air as I started to slide.

  I was sliding down … falling … sliding … falling … sliding …

  Sand flew all around me.

  A deep hole. Some kind of sand pit.

  My hands grabbed at the sides. But the sand flew through my fingers. Sand clung to my wet clothes. Covered my hair … my face … my EYES!

  Sliding … falling … sliding …

  “We … we’re being BURIED ALIVE!” I screamed.

  I landed hard on my feet. “OWWWWW!” Pain shot up my body. My legs gave way, and I fell hard onto my butt.

  Brushing sand off my face, out of my eyes, I started to choke.

  I saw Sheena drop onto the sand beside me. She began coughing and sputtering, shaking herself violently, throwing off sand.

  I spit out a gob of wet sand. The sour, gritty feeling on my tongue made my stomach heave. I took a deep breath and held it.

  “We … we’re alive,” Sheena muttered, furiously brushing sand from her hair.

  I picked lumps of sand from my nostrils. I spit again. Then I gazed up.

  The pit was deep. I could see just a sliver of sky at the top.

  I used the stick to pull myself to my feet. Bending over, I brushed the wet sand off my T-shirt and jeans. “It’s sticky,” I said. “And smelly.”

  “Maybe it’s a trap,” Sheena said. “The pirates set this sand trap. They meant to capture us.”

  “No way,” I said. “The pirates just got here — remember? They didn’t have time to dig this deep hole.”

  “Well … somebody made it,” Sheena said. She stared up to the top. “Maybe we can climb out.”

  She dug both hands into the sand wall and tried to pull herself up. The soft sand gave way, and she slid back down.

  I tried next, digging my hands deep into the sticky wet sand. “Hey!” The sand crumbled, and I toppled onto my back.

  “It’s too soft,” Sheena said. “Can’t get a good grip.”

  “Maybe the stick …?” I said.

  I shoved the stick into the pit wall high above my head. Then, holding on to it tightly, I tried to hoist myself up
.

  No. The sand collapsed on me. I came tumbling back down onto my knees. The stick fell and nearly hit me on the head.

  We didn’t give up. We kept trying. I gave Sheena a boost. She climbed onto my shoulders. Her legs wrapped around my neck, nearly choking me. She kicked sand into my face.

  “Get off!” I cried. “You’re too heavy! This won’t work.”

  “We have to try,” she said. “We don’t want to be trapped down here forever!”

  With a groan, I started to push her up the sand wall.

  But I stopped when I heard sounds above us. Voices. From the beach.

  “Oh!” With a startled cry, Sheena jumped off me. She pressed her back against the sand.

  I froze. And listened to the voices. Men’s voices. And as they came closer, I could hear the words they were chanting … chanting deep and low. The same words, over and over in a frightening, slow rhythm …

  “The bones, they crack; the bones, they creep.

  The men come alive in the briny deep.

  You ended our death, you ended our sleep.

  The men come alive in the briny deep.

  So come with us, come with the men,

  Come meet your fate with Captain Ben.”

  Sheena covered her ears. I peered up at the top of the pit.

  The chanting grew louder. The voices surrounded us. Closer … closer … until they were right above our heads….

  “You ended our death, you ended our sleep.

  The men come alive in the briny deep.

  So come with us, come with the men,

  Come meet your fate with Captain Ben.”

  Sheena and I pressed ourselves tightly against the pit wall. We tried to burrow into the sand.

  But there was no place to hide.

  I looked up — and saw the grinning heads staring down at us from all around the top of the pit.

  My legs were trembling. I could feel my heart racing.

  I counted more than a dozen of them. Most were grinning skeletons wearing plain woolen shirts and trousers or dark jackets and ruffled shirts. Their clothes were stained, and the shredded, rotting cloth barely covered their bones.

  Even more horrifying, three of them had faces. Bloated, distorted faces swollen from the water, with cheeks sagging to their shoulders and eye sockets stretched too big to hold their eyes.