That is an amazing pseudonym.
Slime Lake belongs to one of those series I think of as “Goosebumps clones”—you know, middle school “horror,” possibly created to capitalize on the success of Goosebumps (although for all I know, some other series predated Goosebumps).
The plot is very much “Scooby Doo with young kids and an actual monster”: Marc and his twin sister Terri are spending the summer with their uncle at Slime Lake. The lake used to be connected to the ocean, until the waters receded, leaving it cut off (and filled with monsters, according to local legend).
This summer the lake is slimier than usual, and a mean eco-villain has bought out the refreshment stand at the recreation area.
The book starts (as so many actual Goosebumps books do) with two kids, a boy and a girl, being abandoned by their parents for the summer. Not abandoned on a street corner or anything, but sent to stay with their Uncle Nicholas, a man so taciturn that Marc is convinced he doesn’t even want them there.
Advance warning for everyone who knows me: I’m looking for candidates to dump my kids on now that they’re getting old enough to have convoluted adventures involving monsters and ghosts and stuff. Just kidding. Mostly.
Terri notes that there’s a lot more slime than usual (…gross), and wonders if it’s being caused by pollution. Horror novels (and actually, old horror movies) are my favourite source of ecological concern.
That came out sounding sarcastic but I’m being serious. I love all horror that’s based on the idea that disturbing the natural order leads to trouble, and treating one’s surroundings with care is the way to keep monsters at bay (or on your side, whichever).
Then something even more horrific than the slime gets their attention: a speedboat nearly runs them over. Motor boats aren’t allowed on the lake!
They find out that The Wreck, the lakeside concession stand that used to belong to Pops, has been purchased by some creep named George Quayle. He’s calling Slime Lake “Emerald Shores” now, which is kind of funny, and he has plans:
“It’s just the beginning,” he boasted. “There’s gonna be condos, there’s gonna be time-shares, there’s gonna be a very exclusive hotel. Why, when I’m through with Emerald Shores you won’t even recognize the place.” p. 18
So he’s changing the place, bigly. He’s making Slime Lake Great Again. (Okay, I’ll cut that out, but you were all thinking the same thing, right?)
Marc is kind of an idiot, because he doesn’t see that Terri is only being nice and perky around Mr. Quayle to get him to talk. Marc’s mired in pessimism through the whole book, actually, which again is VERY much like Goosebumps, where there’s always at least one annoying whiny child.
There’s a new lifeguard as well, a crabby teenager named Tiffany who is Mr. Quayle’s
daughter from one of his other marriages niece.
In the middle of the night something making a “long, low, wailing sob” wakes Marc. He sees Terri standing on the dock and assumes she’s making the noise to play a prank on him, but when he gets down there she’s sleepwalking, and the noise is coming from the lake.
When they get back to the house they encounter Uncle Nicholas, who is wearing slime-covered boots.
Mr. Quayle, by the way, thinks all of the monster activity is somehow being caused by Uncle Nicholas to drive him away.
Various other kids from their school are also summering at the lake. I assume these are characters from the series, but this is the first Graveyard School book I’ve read.
The monster activity continues to escalate, with one girl even getting grabbed and dragged (briefly) underwater.
Then one evening when Marc and Terri are alone at their section of the lake, the monster appears and drags Terri under the water. She doesn’t resurface. Marc goes after her, and something gets him too.
When he wakes up he’s in a cave. Terri is there, and Uncle Nicholas, and…a friendly monster named Emmie who communicates telepathically with Uncle Nicholas because he’s the Keeper of the Lake. What.
And Terri and Marc are BOTH going to be his successors. They’ll only be in direct contact with Emmie, but there are other monsters, and secret underwater tunnels that they use to travel to and from the ocean.
Turns out Emmie grabbed them because she knows where evil Mr. Quayle is holding Pops (the original concession stand owner) captive. So they go to rescue Pops, arriving just in time to hear Quayle monologue-ing about how once he’s drowned Pops his property will be sold, and Quayle can buy up the rest of the lake, etc. etc.
Uncle Nicholas confronts him, and Quayle tries to escape in his speedboat. It explodes. Emmie rescues Pops, who got tossed overboard with his hands tied, and then goes after Quayle, depositing him on shore. He’s unconscious but alive.
Finally we learn that Quayle sold the Wreck back to Pops and then disappeared. I’m hoping he got eaten off-screen, frankly.