After he witnesses his father's murder at the family dojo, Hazuki Ryou dedicates his life to finding the man responsible—a mission that takes him from the streets of Yokosuka, Japan to the sprawling metropolis of Hong Kong, and beyond. Soon he will learn that larger, mystical forces are at play as he trains to become the ultimate martial artist in his quest for revenge.

In the peaceful little town of Sakuranomori, a group of young friends are about to bid farewell to one of their own. Due to his parents’ business plans, Sana Hidaka has to move away from his quiet childhood home to the boisterous city of Tokyo. Though it pains him, he must say goodbye to his precious friends—the kind-hearted Aoi Oribe, the spunky Wakatsuki twins, Shuri and Shuusuke, and the cheerful and upbeat Nanaka Yatsushiro. But even though he is reluctant to leave them behind, he believes that no matter how far apart they are, they will always cherish the memories of their friendship. Five years later, Sana, now a 16-year-old high school student, returns to his hometown with the hope of restoring his old life. However, he quickly realizes that although his town may not have changed drastically, the friends he left behind are not who they used to be. Unsettling shadows loom over Sakuranomori as his friends hold new secrets and bear burdens that threaten the bonds they once shared.

While searching through his grandfather's attic, Hikaru Shindou stumbles upon an old go board. Touching it, he is greeted by a mysterious voice, and soon after falls unconscious. When he regains his senses, he discovers that the voice is still present and belongs to Sai Fujiwara no, the spirit of an ancient go expert. A go instructor for the Japanese Emperor in the Heian Era, Sai's passion for the game transcends time and space, allowing him to continue playing his beloved game as a ghostly entity. Sai's ultimate goal is to master a divine go technique that no player has achieved so far, and he seeks to accomplish this by playing the board game through Hikaru. Despite having no interest in board games, Hikaru reluctantly agrees to play, executing moves as instructed by Sai. However, when he encounters the young go prodigy Akira Touya, a passion for the game is slowly ignited within him. Inspired by his newfound rival, Hikaru's journey into the world of go is just beginning. [Written by MAL Rewrite]

Rin Matsuoka’s childhood friend, Sousuke Yamazaki, has recently transferred to Samezuka Academy. Upon their reunion, the two reminisce about their childhood days and reaffirm their wish to swim together. Now with Rin, Sousuke, Captain Mikoshiba’s younger brother Momotarou Mikoshiba, and hard-working Aiichirou Nitori, the Samezuka relay team is formed, and their friendship deepens. However, as tournaments, races, and training go on, the reason for Sousuke’s sudden return begins to trouble him and affect his swimming. Noticing Sousuke’s change, Rin pushes to uncover what is holding him back. [Written by MAL Rewrite]