Plot Details:

Opening Scene:
The episode begins late at night outside the abandoned Silver Ridge Mine. A security guard hears eerie metallic clanging and turns to see a glowing, ghostly figure dressed like an old-time miner with a pickaxe and lantern. The figure charges at the guard, causing him to flee.

Mystery Inc. Arrives:
The next day, the gang arrives to investigate. The mine's owner, Mr. Dawson, explains that recent sightings of the "Midnight Miner" have driven off workers trying to reopen the mine. If the hauntings continue, the mine will be shut down for good, putting Mr. Dawson out of business. The gang decides to explore the mine.

Velma's Accident:
While examining a collapsed tunnel, Velma leans too close to the unstable wall. A loose rock falls, striking her helmet and knocking her unconscious. The gang rushes to help, but when Velma wakes up, she's confused and disoriented—she doesn't remember who she is or why she's there.

Velma's Amnesia:
Freddy suggests taking Velma back to town, but she insists on staying, hoping that continuing with the mystery might help her remember. Though she struggles to recall her identity, Velma begins experiencing flashes of memory—quick glimpses of mine equipment, faint sounds of machinery, and vague silhouettes of suspects. She doesn't understand the significance of these flashes yet, but they subconsciously guide her throughout the episode.

Investigating Without Velma's Insight:
With Velma unable to provide her usual logical insights, the gang has to rely on their other skills:

Freddy focuses on setting traps and analyzing the mine's layout.

Daphne looks for visual clues, using her eye for detail to notice things others miss.

Shaggy and Scooby, while still scared, accidentally stumble onto important evidence during their snack searches.

Clues Found:
The gang discovers signs of recent mining activity in areas supposedly abandoned for decades. Daphne finds fresh tire tracks leading to a hidden tunnel, while Scooby and Shaggy uncover mining tools that look too modern for a ghost to use. Freddy deduces that someone might be using the mine for illegal purposes.

Midnight Miner Attack:
While exploring a deeper tunnel, the gang is confronted by the Midnight Miner. His eyes glow red, and his lantern emits an eerie green light. Swinging his pickaxe, he chases them through the maze-like tunnels, causing rocks to fall and blocking their escape routes. The gang barely escapes by using an old mine cart to ride down the tracks.

Velma's Self-Discovery:
As the gang regroups outside the mine, Velma reflects on her strange memory flashes. She begins to realize that despite her amnesia, she still notices patterns and details that others miss—like the specific type of flashlight bulb the Midnight Miner used and the faint sound of an engine echoing in the tunnels. Though she can't fully piece things together, she feels a sense of determination growing within her.

Suspects:
The gang identifies three main suspects:

Mr. Dawson – The mine owner, desperate to save his business. Could he be scaring people away to cover up illegal mining?

Larry Jenkins – A rival businessman who wants to buy the mine for cheap. Scaring workers off could drive the price down.

Martha Caldwell – A local historian who opposes reopening the mine, believing it disturbs the spirits of past miners.

Final Confrontation:
The gang sets a trap to catch the Midnight Miner, using Scooby and Shaggy as bait. Freddy rigs an old mine elevator with a tripwire, while Daphne positions mirrors to reflect the miner's lantern light and disorient him. Velma, despite her amnesia, insists on helping—feeling that she's close to remembering something important.

Memory Returns and Mystery Solved:
When the Midnight Miner appears, Velma sees the glowing lantern and suddenly remembers everything—the falling rock, her investigation before the accident, and the clues she noticed subconsciously. As the trap is triggered, Velma connects the dots aloud:

The tire tracks and modern tools suggest someone was secretly mining silver.

The sound of an engine matched the hum of portable mining equipment.

The glowing lantern was a projector hidden inside an old miner's lantern, creating the ghostly illusion.

Unmasking the Villain:
The trap works, capturing the Midnight Miner, who is revealed to be Larry Jenkins, the rival businessman. He was using the disguise to scare people away so he could mine silver illegally and buy the mine at a low price. His high-tech lantern and costume created the ghostly illusion, while hidden speakers amplified the metallic sounds.

Ending:
With the culprit caught, Mr. Dawson can safely reopen the mine. Velma, fully recovered, is relieved to have her memories back but reflects that her temporary amnesia taught her something important: even without her usual logic and facts, her instincts and determination still made her a valuable part of the team. Scooby and Shaggy, of course, are just happy that the mystery is over and celebrate with a well-earned snack—only to discover that their sandwiches have been stolen by a mischievous mine squirrel, ending the episode with the classic Scooby-Doo group laugh.