Pete thought. “Maybe pile up some of those big stones to look natural — but give Laura a clue?”
“Or,” Bob said, “maybe plant a tree? A special tree like one they had at home in Scotland?”
“Yes,” Jupiter said, “that’s possible, Records.”
“Maybe a mirror!” Pete exclaimed. “On the ground, or in a tree, and Laura would see it from some special spot!”
“From a window where she sat at home,” Jupiter said. “Or from the top of the lodge’s tower!”
“Gosh,” Bob said, “any of those would work! I’ll bet one of them is right, Jupe!”
Jupiter nodded, and stared out of the back of the truck at the first houses of Rocky Beach.
“Only one thing bothers me a little,” the Leader of the trio said slowly. “Old Angus’s letter said to remember the secret of Phantom Lake — the phantom that watches for enemies coming up the lake. A hidden cavern doesn’t seem to fit in with that legend.”
“Maybe when we find the cavern we’ll make the connection,” Pete said.
“Yes, perhaps you’re right, Second,” Jupiter agreed.
Hans dropped Bob and Pete at their homes and drove on to the salvage yard. When Jupe got home, he was too excited to sleep right away. He had some hot chocolate and told Aunt Mathilda and Uncle Titus of the day’s adventures. Uncle Titus hurried straight out to inspect what Mrs. Gunn had sent him. Aunt Mathilda decided that a big hole hidden underground sounded exactly right to fit the riddle.
“You’ll find it in the morning, I’m sure,” she said. “Now I want you in bed, young man. You’ll think much better when you’re rested. Off with you!”
Jupiter lay awake for a long time watching the Christmas lights of Rocky Beach. But at last he fell asleep, still thinking of the hidden room, the big stones, the sluice timber, and Cabrillo Island where old Angus had gone to get…
Jupiter sat bolt upright in his bed!
He blinked, still half asleep. It was dark outside his window, but his dock showed that it was almost 8.00 a.m. Then he heard the drumming on the roof, and realised that it was raining hard outside.
But he didn’t think now about the rain.
He sat there and stared at the wall. He knew the whole answer to Angus Gunn’s riddle!
19
The Riddle is Solved
Jupiter dressed and called Bob and Pete. He told them to meet him at the salvage yard in fifteen minutes. He had the answer!
“I’ve been dumb,” the stout leader of the trio moaned. “I should have seen it long ago. Hurry!”
He called Cluny at Phantom Lake.
“I think I know where the treasure is, Cluny,” Jupiter declared to the sleepy boy on the other end of the phone. “Get a pick and shovel and your raincoat, and wait for us. Hans will drive us out,”
He hurried downstairs to have a quick bowl of cereal. As he gulped his milk, the telephone rang. It was Professor Shay.
“Jupiter?” the professor said. “I’ve been lying awake in bed thinking about our hidden room, and I’ve had an idea of how old Angus could have marked it! The phantom — ”
“There isn’t any hidden room. Professor,” Jupiter told him. “I’m certain I know the answer now!”
“What?” Professor Shay cried over the telephone. “Not a hidden room? Then…? Tell me, Jupiter!”
“I’ll tell you at the lake. Meet us there.”
“I’ll get dressed at once!” the professor said.
Ten minutes later, The Three Investigators huddled in the rain in the salvage yard. Pete and Bob could barely contain themselves. When Hans arrived with the truck, they clambered into the covered back and faced Jupiter.
“What is the answer. First!” Bob demanded.
“Tell us!” Pete echoed.
“All right,” Jupiter said, with a maddening grin. “I was asleep, and the hidden room theory was bothering me, and something Bob said when we rode home must have popped into my head. Then I saw the whole thing!”
Pete groaned in the bumping truck. “What did Bob say?”
“He said,” Jupiter intoned solemnly with his love of drama, “that maybe old Angus planted a special tree at Phantom Lake. And that’s exactly what Angus did!”
“A tree?” Pete gaped.
“Not a tree that he knew from Scotland, as Bob thought,” Jupe went on, “but a tree that would make Laura think of home. He went to Cabrillo Island and bought one of those twisted cypress trees that look like phantoms! He planted a phantom at Phantom Lake!”
“Wow!” cried Bob. “All we have to do is find an old cypress out at Phantom Lake!”
“But,” Pete objected, “where do we look? There’s acres and acres of trees out there.”
“The rest of the riddle tells us.” Jupiter beamed. “Think of the steps to the puzzle again. First, the miners and the sluice timber from Powder Gulch. Pete was absolutely correct — miners dig best, and they did dig a big hole. And there is one vital fact about sluice timber we completely overlooked. Why did old Angus have to have sluice timber? Not just planks, or mining timbers, but sluice timber?”
“Why, Jupe?” Pete sighed.
“Because sluice timber is specially cut and fitted to hold water!” Jupiter declared. “A sluice holds water in, but old Angus used it to hold water out!”
Bob stared. “Out of where, Jupe?”
“Out of the big, long hole he had the miners dig for him,” Jupiter said. “He had to keep water out of the hole while it was being dug. Then he bought ten large stones to use as stepping stones. He got a cypress from Cabrillo Island. And what he bought at Wright and Sons was a ship’s lantern!”
“The island in the pond!” Bob and Pete cried together.
“Exactly,” Jupiter crowed. “Old Angus built that small island in Phantom Lake! That was Laura’s surprise. Everyone thought old Angus found the pond with the island in it, just like home, but he didn’t. He built the island!
“Originally there must have been a narrow peninsula jutting out into the pond. Angus built a barrier of sluice timber on each side, cut a channel across the peninsula, put the big stones in to be the Phantom’s Steps, and let the water back in. He had an island then. He put a ship’s lantern from Wright and Sons on a pole for a beacon, and planted a twisted cypress to recreate the legend of the phantom!
“He built a miniature replica of what he had loved at home — the view down the loch. That was his surprise present for Laura.” Jupiter paused for breath. “Then, when the Captain of the Argyll Queen and his men appeared, Angus used his island as a hiding place for the treasure. He left the letter and the second journal as clues!”
Bob and Pete were silent in admiration of old Angus’s clever riddle and Jupiter’s solution of it.
“No one ever knew the island was man-made?” Bob said finally.
“No one besides Angus, except the miners who dug it,” Jupiter said. “Miners in those days were mostly drifters, and even fugitives. By the time anyone started looking for the treasure, most of the diggers had probably gone away. Angus’s family assumed that the island was natural, and never knew about the miners because they never read the second journal!”
“But we found it, and now we’ll find the treasure!” Pete exclaimed.
“I’m certain of it,” Jupiter declared.
Bob said, “One thing still confuses me, First. What did old Angus mean when he wrote about seeing the secret in a mirror?”
“Maybe the pond is like a mirror?” Pete suggested.
Jupiter said, “I think I can explain that, too. But first I want to go to the pond and — ”
The truck had turned on to the side road to Phantom Lake some minutes earlier. Now Hans slammed on the brakes, throwing the boys backwards. They recovered, and jumped out. Hans was already out of the cab, hurrying forward.