Ep. 19: Houtarou solves a fabricated mystery regarding counterfeit currency to prove his theoretical point.

Houtarou challenges Eru to create a random mystery to demonstrate that theories can arise from anything. Eru selects a case where students visiting a local stationary store are summoned to the staff room. She takes the exercise seriously, growing dissatisfied with Houtarou’s initial attempts. He recalls a news flyer on a school bulletin board and deduces that the students are assisting authorities in identifying the source of a counterfeit 10,000 yen bill received by the store clerks. Eru is impressed by this logical conclusion, though both forget the original purpose of their game. The following morning, a newspaper confirms that the counterfeiters have been arrested, validating the accuracy of Houtarou’s improvised theory.

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