The Prestigious Classic Lit Club's Activities

Unable to stand the inactivity of the Classic Lit Club, Eru announces to Houtarou that they need to publish club's traditional annual anthology named Hyouka. While looking for the Hyouka past issues, she drags Houtarou to the school library where they encounter Satoshi and Mayaka. Mayaka tells them a mystery which neither she nor Satoshi can solve. This ignites Eru's curiosity, and she forces Houtarou to start an investigation.

Synopsis
With the president of the Classic Lit Club chosen as Eru Chitanda, Houtarou Oreki continues his lazy days, reading a book in the club room. Unable to stand the inactivity of the club, Eru announces that they would create the traditional anthology created by the club every year as the Kanya Festival was approaching. Though he is not up for it, Houtarou is forced by Eru to find older copies of the Hyouka made by past club members.

In the library, the duo encounters Mayaka Ibara, a childhood friend of Houtarou, who is the library attendant at that time. The two ask about the older copies of the anthologies, but Mayaka doesn't know, along with Satoshi who happens to be there. Impatient and wishing to go back to reading in the club room, Houtarou attempts to leave, but in order to keep him together with the group, Satoshi makes a comment about a mystery. This hooks Eru, which ends up having her holding Houtarou back from leaving the library.

The mystery Satoshi mentions about is one he and Mayaka had been trying to solve for the whole day. "Every Friday, for five consecutive weeks, a student had checked a large reference book, only to return it at the end of the day. Every time, it was a different student, with the same book." Houtarou, as usual, is not interested, leading him to wanting to leave, but Eru pulls him back, as she is the one interested.

Weekly Book Check-Out & Return Case
As the Library attendant every Friday, Mayaka has noticed that every morning break, a female student comes by to pick up a thick textbook, only to return it after school the same day. You can borrow any book for up to two weeks, yet the book was returned, as said, on the same day it was checked out. This has occurred for five consecutive weeks now, and each time, it is a different girl who takes and returns. Between the morning break and after school, there is only 3 class periods and 3 other shorter breaks, making reading the book very improbable. One guess was that the book was used to form a certain code when returned, but the book return section makes this feat very difficult, since the book could be placed in any fashion.

Solution: For five weeks, the same textbook has been taken at morning a break and returned after school, by different girls. Yet, all the girls were in the same second year and were also in either class D, E or F. If there isn't much time to read the book during the given short breaks, and if the book was not taken home at all, the book must have been used for classes instead. And if the girls collaborated on a certain work using the book, the chances the book was used for such events is more likely. Only a few classes collaborate between classes, but with Eru's hint that the book smelled of paint, it was easy for Houtarou to deduce that the book had been used in the art classes, which he was right.

Trivia

 * This episode is adaptation of Ch. 1 "Letter From Benares" and Ch. 3 "The Activities Of The Prestigious Classics Club" from.
 * During the second scene of the episode in the anime or second to third page in the novel chapter, there's a pun attempt by Houtarou when Chitanda says that the current activities are fruitless (不毛, fumou), with Houtarou replying asking if she means "two crops a year" (二毛作, nimousaku). The pun is based on the readings of the first kanji of each word. 不 (that normally means "negative prefix") have the same (partial) reading of 二 (two) in some words, "fu". The pun ends with Chitanda explaining that she doesn't mean, and asks if Houtarou was telling a pun, in front of failure Houtarou just deny and blush. This pun isn't correctly adapted or explained in the official English release of the anime, leaving the scene meaningless to people unaware of it.