Due to an unusual ability to see strange creatures called youkai, Takashi Natsume has never fit in. Passed around from one foster home to another, he was left isolated and lonely. Over time, he has accepted that no one would ever believe him and has closed himself off to his current caretakers and classmates. When Natsume accidentally breaks an intangible barrier, he frees Madara—a mighty spirit in the form of a lucky cat. Madara notices that Natsume bears a remarkable resemblance to his late grandmother Reiko Natsume, an outcast girl who became known across the youkai world for creating the Book of Friends. It is now in Natsume's possession, along with its power to call upon the written names of the youkai Reiko had defeated. With no interest in its powers, Natsume decides to keep the book for the sake of his grandmother's memories and to protect it from scheming youkai. Therefore, he makes a deal with Madara: he will hand him the book once his time is up, and in turn, Madara will act as Natsume's unofficial bodyguard, nicknamed Nyanko-sensei. With his newfound goal of freeing those Reiko had sealed, Natsume's relationship with both youkai and humans slowly begins to improve.

Despite being polar opposites, Makoto Smile Tsukimoto and Yutaka Peco Hoshino have been best friends since childhood. Although the overly confident Peco strives to be the best ping-pong player in the world, he often skips practice, earning the ire of his fellow teammates on the Katase High School ping-pong team. Meanwhile, Smile—in spite of his innate talent for the sport—cannot help but hold back his full strength when playing against others. Through their mutual love for ping-pong, the two have developed a bond that is seemingly unbreakable. When Peco hears that an ex-national team player from China is coming to Japan, he drags Smile over to rival Tsujido High School to observe them. The subsequent trip leads to a clash between Peco and Kong Wenge, who overwhelmingly defeats the former in one game. Stunned by such a comprehensive loss, Peco finds himself questioning why he plays to begin with. Seeing his potential as a player, Katase's coach begins to train Smile to overcome his hesitation, but he is reluctant to play if it is not for enjoyment. As the two struggle to find meaning in the sport, a plethora of stronger players—each with their own internal strifes—await them at the inter-high tournament, where only the very best can persevere. But when these young athletes let their unbridled ambition go unchecked, the hardships they face paint a somber reality as they pursue glory.

Hikari Hanazono has always been able to do things that normal people cannot. As a child, she assumed no one could beat her—until she met Kei Takishima. Thinking she would win, Hikari challenged him to a match. But things didn’t go as planned; she lost not once but each time she rechallenged him. From that point on, she has sworn to best Kei at everything, ranging from academics to athletics. To achieve her goal, Hikari enrolls in the same school as Kei—Hakusenkan, a prestigious institute for the wealthy. As a pair, they hold the top two rankings in school and are among seven of the academy's best students in a class known as Special A. While Hikari treats Kei as a rival, she is completely oblivious that he harbors hidden feelings for her. Together, the members of Special A deal with competition, friendship, and just a bit of love.

As a child, Chihaya Ayase had only one dream: to see her elder sister Chitose become Japan's most successful model. However, upon defending her ostracised classmate Arata Wataya from his bully—Chihaya's childhood friend Taichi Mashima—she discovers the world of competitive karuta and soon becomes enamoured with the sport. Based on the Ogura Hundred Poets anthology, this card game where poems are studied requires excellent memory, agility, and a tremendous endurance from the players. Full of hope, Chihaya joins the Shiranami Society together with the newly reconciled Arata and Taichi, embarking on an exciting journey for the title awarded to the top-ranked female player—Queen of Karuta. Since middle school, Chihaya grew distant from a dispassionate Taichi and separated from Arata. However, in order to improve her skills, Chihaya decides to create a karuta club in her high school. With the help of Taichi, another veteran player, and a few spirited newcomers, Chihaya's new-founded Mizusawa Karuta Club aims for victory in the Omi Shrine's national championship.