The position of the junior high school principal's office is by the spring. When the player just entered 3 to 1, he felt that the atmosphere around him was not quite right. It turns out that the whole college is haunted. After entering the map, I talked to two NPCs. They opened a single room on the left and the organ in the upper right corner. There is also a topaz in the single room on the left. Remember to collect it when you see it. The mechanism in the upper right corner explodes with a bomb, steps on the spring, and then you can jump to the back secret room. You can get new fans by talking to NPC after you go in. If the player clears all the world maps, he can go back to this NPC and get the reward level from her. Go straight from the hidden room to the left, and you will see many rooms with the names of classrooms written on them. You need some special props to open these classrooms, but these are side tasks, so you can leave them alone for a while and continue. After finding the second piece of topaz, push away the stone and detonate the remaining bombs, and you can leave the area. Go back to the map where the glasses girl NPC started, talk to her and learn some information about the haunted incident in the college. Get a ghost device that can move backstab from her, push the stone on the right and unlock the convenient passage to the hidden classroom. Light up the books in the library, get a prop and return to spring. Talking to Spring can open the junior high school principal's office, unlock it and enter directly.