Raign, Brett, and Joy set off elaborate pranks to earn a stay in detention which is located in the old library which is also the suspected entry point to Alexander Graham Bell's secret lab. Norman also enters the room and even finds the solution to the first clue which leads to the tunnel entrance.
Noise of the tunnel entrance find attracts Principal Lounsberry. It's Norman who buys time for the group to restore things and resume their proper place in the room. Day two and more pranks gets them into the tunnel where a secret door is discovered.
Day three pranks get them back in the tunnel to decipher the clues to getting the secret door opened. Now all they need to do is pick some books to burn.
Norman watches Brett be a bully and is very upset with him. Just as they are about to go down into the secret room, they get a visitor, Miss Marner, who wants to do team building exercises. In the end they still have time to open the secret door.
Out of red paint sends Miss Marner to a great prank and onto detention for the team. In the dark and spooky room the next clue and puzzle is revealed. At the end of detention Principal Lounsberry takes the book of clues to lock it in his safe.
The group must plan a break-in into Principal Lounsberry's office. All goes almost well, at least they get the book back. They also find out that Bruno Black has just purchased the school and plans to tear it down.
A new plan is needed if the school has only two weeks left. Down in the tunnel they spend more time on back-stories than figuring out the new clues. Running upstairs they find Principal Lounsberry waiting on them and he gives them a two week suspension.
Having been suspended they now break into school, but the back door is unlocked and the lights are on. They find Bruno Black dancing in the hall. As they decend into the tunnel a noise attracts Bruno into the detention room where he finds the open tunnel hatch.
Confronted by Bruno Black, who reveals he also searched for the secret lab back in 1984 and failed, tries to force the kids out only for them to actually find the lab and to find themselves trapped inside.
Trapped in Bell's secret lab the kids work on getting out while above them Principal Lounsberry and their parents search for them. After a rescue, the school is placed on the Historical Treasures list and can never be torn down. It almost seems it's all over, except for the treasure map Brett just happened to find in the lab but that's another story.
