Since the beach was deserted, the kids had their pick of picnic spots. After cooking the first of the hot dogs, Ssshaggy noticed the gang was one member short.
"Hey!" he said. "Like, where's Scooby-Doo? He's supposed to be helping me!"
Velma looked up from her book. "He went moon-surfing," she replied.

"Rooby-rooby-roo!" Scooby yelled from the ocean. nfortunately, instead of catching a wave, his paw caught a glowing ghost in deep-sea diving gear!
"Groooooan!" moaned the spooky diver.
"Ripes!" Scooby yelped, quickly spinning the surfboard and dog-paddling back to shore!

The seaweed-covered ghost stepped out of the water. "Mooaaaaannnn!"
"Zoinks! A sea-going spook!" Shaggy yelled, hiding inside Velma's beach umbrella.
"You can relax, Shag...he's gone, "Fred told him. "But he did leave behind one clue."
"Glowing footprints!" Daphne said. "I wonder what's behind this mystery!"

"Listen to this," Fred said the next day. "Another boat vanishes! Coast guard baffled!"
"I wonder if the missing boats are connected to that spooky diver we saw?" Daphne asked.
Fred continued to read the newspaper. "Fisherman Ebenezer Shark claims this is the work of the ghost of Captain Cutler!"
"Let's pay this Shark a visit!" Velma said.

Ebenezer Shark was eager to talk, and invited the gang into his vessel.
"Aye, I seen the ghost of Captain Cutler! A ghostly glow moving through the fog," Shark said in a raspy whisper, his sinister eyes narrowing down to tiny dots.
"Months ago, Cutler's boat collided with one of those fancy yachts from the marina, sending him down to the graveyard of ships. As he vanished beneath the waves, Captain Cutler vowed he'd return and get revenge."
A series of barks interrupted the story.

Down in the hold, Scooby had discovered a familiar-looking diving suit!
"Your pooch stumbled onto me old gear," Shark said, helping to free the dog.
"If you want more about Cutler, see his wife up at the old lighthouse."
"There's something mighty fishy about Ebenezer Shark," Velma said after they left the boat.
"Yeah, he looks more like a barracuda!" Shaggy cracked.
"Daph and I will keep an eye on Shark," Fred said. "You three talk to the widow Cutler."

At the lighthouse entrance, Shaggy, Scooby and Velma were involved in a debate:
"Go ahead, Scoob-knock on the door," Shaggy said.
Scooby whimpered, holding his paw as if it were injured.
"Look at him!" Velma laughed. "What a ham!"
"Looks more like a chicken to me!" Shaggy retorted.

Inside the gloomy lighthouse, Shaggy, Velma and Scooby looked for Cutler's widow.
"Like, wow! This place is furnished like a Halloween store!" Shaggy said.
"Thank you, dearie!" a high-pitched voice cackled, making Shaggy jump into Scooby's arms. "We witches adore a haunted atmosphere!"
"We're here about Captain Cutler...we think we saw his ghost!" Velma explained.
"You did! I used my witchcraft to bring my husband back from a watery grave!"

"Whew!" Shaggy said, breathing a sigh of relief once he was outside the light-house. "Am I glad to get out of that scary pad! I don't want any spells cast on me!"
"If she's a witch, I'm a hobgoblin," Velma snorted. "Our next stop to solving this mystery is to find Captain Cutler's ghost."
Shaggy pointed at the beach. "I think he's found us-check it out!" A glowing mass of yellow-green seaweed was inching along the edge of the beach! However, before they could grab it, the glow vanished into a drainpipe.

After eating a Scooby Snack for courage, Scooby dove into the pipe and pulled out the glowing clump of seaweed. An engry mouse was hanging onto the other end! The two struggled in a tug-of-war before the rodent gave up.
"Looks like you found a clue, Scooby-Doo!" Velma said.