In my high school, if you missed three assignments, you got a lower grade. In Shadyside High, if you miss three assignments, you wind up in Saturday school. It seems like Mr. Savage, the new school principal, decided that detention doesn't work anymore so he implemented Saturday school. Elaine winds up there because she missed turning in three assignments in math class.
On hand are the typical bad seeds. Darlene wears rock band shirts and dark eyeliner, while Bo gets in trouble for doing dozens of things every day. Max and Jerry both seem pretty cool, but they do whatever Bo tells them. Savage warns them about acting up and leaves, but Bo hurls a switchblade at him, which hits the bulletin board.
Darlene suggests they do something fun after calling Elaine a yuppy. They head to the cafeteria because nothing says fun like stealing food. Jerry takes iced tea, Max takes ice cream sandwiches, Darlene eats chips, and even Elaine takes some chocolate milk before they realize that Bo is missing.
They hear a noise and think it's Savage, but it's actually Bo with a butcher knife in one hand and blood dripping down his neck. He gurgles and falls over dead, but while everyone else flips out, Elaine realizes that he's faking. He laughs it off, explaining that it's just ketchup because if anything looks like blood, it's totally school ketchup.
When another noise happens right outside the cafeteria, they run away because it's probably savage. Since Bo apparently saw The Breakfast Club a few too many times, he knows exactly how to get around the school without the principal catching them. On their "daring" escape, they find a way into the auditorium. Bo and Max ruin some sets by tossing black paint on them, which annoys both Elaine and Jerry.
Elaine takes a break to get away, goes deep behind the stage, and falls through a rotten spot on the floor. The others find her and climb down, and Bo realizes that they're in the Labyrinth. Shadyside built a bunch of bomb shelters and connected them with tunnels, which defeats the purpose of a bomb shelter. For years, kids went down there to party and have fun.
Even though Elaine fell eight to ten feet, she's fine enough to get up and walk. Bo claims that he can find a way out, so they start off. She keeps an eye out for a souvenir that she can show her friends, but all she sees is trash. They do find a newspaper from 1971, which has a review of an album from The Doors and a picture of a girl in a vest made from Coke cans. I'm really curious what this looks like. After browsing through the newspaper, they realize that they are completely lost.
Bo conveniently has a bottle of lighter fluid with him to make torches, but they get lost in the tunnels. They try going back the same way, get even more lost, and realize that there's water rising. Elaine notices a ledge that gets them above the water, but as they're inching along, she trips and falls into the water. Bo manages to save her and even gives her his jacket to stay warm. They go even further into the tunnels, and Bo notices something off about a wall they pass.
He digs through the mortar and opens the wall, telling the group that it seems a lot older than any other spot. A weird red mist comes drifting out from the hole in the wall, and flows toward Max. The mist picks him up, and they all hear a popping sound as his arm gets ripped up. Max starts screaming, and Bo tries to help him, but the mist just keeps squeezing his body. When the mist finally settles, there's nothing left of Max. The mist moves down the tunnel, and Bo rushes after it.
Jerry and Darlene want to leave, but Elaine has the only torch still it and she refuses to go. After a short argument, Darlene tells her that they will leave her ass there if she doesn't want to go, and she pretty much says that they'll take the torch over her dead body, which makes Elaine agree with them. Darlene grabs the torch from her, they run off, and Elaine realizes that she can't run very fast on her injured ankle. She sees them run faster and the torch disappear.
No worries though because they get lost and stop so she conveniently has time to catch up. They only get a few feet down the tunnel before they run across a dead body. Darlene screams, tries to run from Elaine who now has the torch, knocks that torch out of her hand, and the world goes dark. Elaine remembers that Bo had a lighter in his pocket, and since they're pretty sure the body is Bo, she tells them. Darlene and Jerry both flip out, so Elaine has to crawl over to his body in the dark. Turns out that it wasn't Bo, just a pile of clothes.
Bo does come running up to them though. He helps them make some new torches and tells them that he found the mist and Max. The mist wouldn't let go of his body, and when it grabbed Bo, he finally let go and took off running. The whole group find their way back to the original spot where Elaine fell, but she smells the red mist coming.
Darlene knocks her down to climb up the ladder, and Elaine tells Bo to go next so he can pull her up. The mist hits just as he reaches the top, but it grabs Jerry. Elaine tries to save him while still holding on to the ladder, and she manages to grab his hand. Everyone screams, and the red mist wraps around her stomach.
She sees Jerry's eyes bulging and his body changing, and Bo tries to grab her and pull her up. They lose their balance, she falls, and he lands on top of her. Darlene is somehow on the ladder again and can't get a good enough grip to climb the rest of the way up because the ladder started breaking away from the wall. Bo tells her to just let go, and she falls on top of him.
They go back to the hole the mist came through, and Bo decides to climb in and see what's there. He finds a long tunnel through the dirt and they follow him through it. They eventually find a small room with six skeletons inside, and they've heard rumors for years that six kids went missing down there. The kids wrote their names on the wall in red paint, but on another wall, they find that someone scratched Mr. Savage's name in the brick. It looks like there was a massive cave in.
The red mist comes back, and Billy lures it to him so the girls can escape. When the mist hits the skeletons, the bones come to life and chase the girls. Elaine tries to help, but Darlene gets killed. She rushes through the tunnel, notices the ground shaking, and sees a second cave in start happening.
When she gets out of the tunnel, she runs right into Savage. He has a lantern and was trying to find the missing kids. Billy somehow gets through the tunnel far enough to stick his hand out, and they dig him out of the dirt. Elaine accuses Save of killing some kids, and he confesses what happened.
Years ago, he went to a party in the Labyrinth with six of his friends. While they were goofing off, someone knocked over a bag of beer, and he left through the tunnel to grab the cans. The cave in happened, and his friends were trapped. The next day, he came back with bricks he took from his dad's construction company and bricked over the entrance so no one would know what happened.
They figure out that the kids were still alive after the cave in and made their way through the tunnel only to encounter the brick wall he put up. The red mist comes back, and they all see the faces of the dead kids in it. The mist attacks Savage, but before he dies, he gives them directions on how to get out of the tunnels. Once the mist kills him, it disappears.
Elaine and Bo follow his instructions and find a ladder that leads down from the boiler room. For a school that doesn't want kids to have access to these underground tunnels, it doesn't do a very good job of hiding them. They have no idea what to tell people about what happen but decide they can figure it out later.
*Just one little comment here. Bo mentions that he's heard stories about the Labyrinth for years and one of his friends found it one day but forgot how to get there. If there's an entrance in the boiler room, how do more kids not find it?
*Okay, one more comment. Why would Savage even think to look for the kids down there? Most teachers would just assume they took off, especially since they had no supervision.