Maya and Singh treat the strange notes that are performing in lockers as mere fun but when they become dark, exposing secrets and tricks that could ruin friendships and people's reputations, they decide to find out the truth by working with their friends and examining every inch of their hypercollege including busy classrooms, silent library, abandoned storage, dark cells.
With each clue, they get closer and closer to revealing the person behind all of this. However, the more they search, the greater the mystery becomes. The most powerful things that can be used to solve the puzzle in the story Secret of the Hallway are friendship and sharp observations.