Rejoining the others, Velma used her biology book to identify the seaweed.
"This type is found only in the Graveyard of Ships," she read.
"That's where Captain Cutler went down!" Daphne said.
"Maybe that's where we'll find his ghost-and an answer to this mystery," Fred said. "Shark left about an hour ago. I think we need to go for an on-site inspection!"

After suiting up in rented scuba gear, the gang took their motorboat to the Graveyard of Ships.
"If we're going to find that ghost, we'd better split up," Fred said.
One by one they dove over the side, swimming to the bottom where numerous wrecked ships rested on the ocean floor like broken tombstones scattered across a cemetery.

Looking through the porthole, Daphne spotted a seated figure at a cabin table wearing an old style diving helmet. Swimming inside, Fred, Daphne and Velma soon found the suit to be a rusty relic from an earlier time, but before they could turn to leave, the door slammed behind them and was bolted shut!
"Oh, no! We're trapped," Velma said.

Meanwhile, Scooby had found another clue. Inside the hold of an old ship, Scooby was looking at shelves of air tanks. Some of the tanks were empty, but most had a full charge of air.
"This is somebody's private storeroom of scuba tanks!" Shaggy told him.
Unfortunately for the pair, the owner picked this moment to show up in all of his glowing glory!
"Zoinks! Captain Creepy! Swim for it, Scoob!"

Shaggy and Scooby weaved in and out of the many wrecked ships, searching for a place to hide.
"Over there!" Shaggy said, pointing to a closed cabin door.
Busting their way inside, they were surprised to discover Fred, Velma and Daphne!
"Nice save!" Fred exclaimed.
"Look at this," Daphne said. "More footprints!"

Following the trail, the gang soon discovered the glowing tracks came to a stop in front of a rock wall.
"I'm pooped from all this swimming," Shaggy said, sitting on a rock that triggered a secret entrance into the cliff! Swimming through the passage, the gang found fresh air when they broke the surface of the water...along with what appeared to be a small fleet of stolen boats, many of them with fresh coats of paint to disguise their identities!

"We're in a giant underground cavern!" Shaggy exclaimed. "Get a load of all those yachts!"
"I guess this wraps up our mystery," Daphne noted, "if we can wrap up that ghost."
Fred grinned. "Not wrap him up-wash him up!"

Fred's plan to capyure the ghost of Captain Cutler was simple. First, attract the sppok's attention to a ramp located at one end of the vavern. When the ghost arrives, use a high-pressure fire hose from one of the yachts to blast him down the ramp and into a waiting net. Velma was in charge of the water control, while Fred and Daphne held the hose. Shaggy and Scooby waited at the net.

As planned, the ghost of Captain Cutler appeared at the top of the ramp. Velma turned on the water, but the slippery hose moved like a bucking bronco, spraying water in all directions. Scooby took the brunt of the blast, which knocked him into a small motorboat that sped about the cavern out of control. Shooting up the ramp, dog and boat flew into the air like a rocket!
"Rooby-rooby-roo!" Scooby yelled as the craft plummeted downward, smashing over the top of the ghost and pinning the spook's arms to his sides.

"Well, let's see if we've caught ourselves a Shark," Fred said, removing the ghost's diving helmet. However, the face revealed underneath belonged to a man none of them recognized!
Then, Shaggy picked up a piece of seaweed. Holding it to the man's chin, he asked, "Does this help remind you of a certain picture we saw on the widow Cutler's wall?"
"Captain Cutler!" Velma said.
"My perfect scheme-ruined, thanks to you meddling kids!" Cutler sneered.

The next day, the gang gathered for grape sodas.
"That was some plan Captain Cutler and his wife had!" Fred said.
"Spreading the phony story about Cutler's boat sinking and then stealing the boats from the marina was one deep-sea hoax."
"Too bad for him his diving suit got covered in that kooky glowing seaweed," Shaggy agreed.
"I guess that wraps up another mystery," Velma said, before being interrupted by a loud slurp!

"Gee whiz, Scoob-I think you need a refill," Shaggy said.
Scooby disagreed. As the dog gave a final giant sip on his straw, the other four glasses on the table emptied like magic!
"How did Scooby do that?" Daphne wondered.
"I guess that's another mystery," Fred replied.
Scooby smacked his lips and grinned. A mystery, yes-and he was't telling!