A possible concise summary is:
The speaker is a big brother who has to deal with his mischievous little brother Paul Berger, who gets into trouble at school. He finds out that the school director is a kidnapper who feeds children to a monster in an abandoned mine. He tries to rescue his brother and other children from the director and the monster, using weapons and explosives. He manages to defeat them by feeding the monster normal food, which weakens it. He then decides to go eat burgers with his brother.
Here are the key facts extracted from the text:
1. Paul Berger's little brother is in trouble at school.
2. The school principal has called Paul Berger to come to school because his little brother has done something wrong.
3. The little brother has triggered the emergency signals three times.
4. The little brother is accused of not doing his homework and pulling a fire extinguisher.
5. The little brother is also accused of bringing a firecracker to school.
6. Paul Berger's little brother has to go to detention.
7. Paul Berger decides to investigate what's going on in the detention room.
8. They discover that the teacher is taking the students who are in detention to an abandoned mine.
9. They overhear a voice that sounds familiar to Paul Berger.
10. The voice is revealed to be a woman who has been feeding on children.
11. The woman has been making the children who are in detention disappear.
12. Paul Berger and his little brother try to escape from the woman.
13. They discover that the woman is taking the children to a cemetery to perform a ritual.
14. Paul Berger and his little brother try to stop the woman by stuffing something into her mouth.
15. The woman's strength is dwindling because she has not eaten children for a while.
16. Paul Berger and his little brother use a baseball bat to try and kill the woman.
17. They use a Molotov cocktail to try and finish her off.
18. The woman is finally defeated, and Paul Berger's little brother is safe.
19. The director of the school is also defeated, and a new teacher is appointed.
20. Paul Berger and his little brother are finally able to eat and relax after their ordeal.