In a universe that is both familiar and different, Yuki Nagato presides over the Literary Club at North High School. Being a shy bookworm and gamer, her only companions in the club are her overly-cautious friend Ryouko Asakura and the average Kyon. Despite the small group, Yuki cherishes the peaceful and quiet moments shared with her friends, especially Kyon, who she secretly admires. At times, they are joined by Tsuruya and Mikuru Asahina, two friends with contrasting personalities. One frigid day in December, Yuki is approached by Haruhi Suzumiya from a prestigious school, who begs her to draw strange symbols on the ground in an attempt to capture Santa Claus. Haruhi's goal is to find aliens, time travelers, and espers. Unexpectedly, Haruhi and her friend Itsuki Koizumi arrive at the clubroom, declaring themselves official members, with Haruhi taking on the role of executive president. With Haruhi in charge, their once peaceful Literary Club turns into a series of tumultuous and chaotic misadventures, and Yuki and her friends get caught up in the madness. During these trying times, Yuki and Kyon's relationship deepens, providing hope for Yuki's infatuation to blossom into something more.