"Mushi": the most basic forms of life in the world. They exist without any goals or purposes aside from simply "being." They are beyond the shackles of the words "good" and "evil." Mushi can exist in countless forms and are capable of mimicking things from the natural world such as plants, diseases, and even phenomena like rainbows. This is, however, just a vague definition of these entities that inhabit the vibrant world of Mushishi, as to even call them a form of life would be an oversimplification. Detailed information on Mushi is scarce because the majority of humans are unaware of their existence. So what are Mushi and why do they exist? This is the question that a "Mushishi," Ginko, ponders constantly. Mushishi are those who research Mushi in hopes of understanding their place in the world's hierarchy of life. Ginko chases rumors of occurrences that could be tied to Mushi, all for the sake of finding an answer. It could, after all, lead to the meaning of life itself. [Written by MAL Rewrite]

The aloof protagonist: a bookworm who is deeply detached from the world he resides in. He has no interest in others and is firmly convinced that nobody has any interest in him either. His story begins when he stumbles across a handwritten book, titled "Living with Dying." He soon identifies it as a secret diary belonging to his popular, bubbly classmate Sakura Yamauchi. She then confides in him about the pancreatic disease she is suffering from and that her time left is finite. Only her family knows about her terminal illness; not even her best friends are aware. Despite this revelation, he shows zero sympathy for her plight, but caught in the waves of Sakura's persistent buoyancy, he eventually concedes to accompanying her for her remaining days. As the pair of polar opposites interact, their connection strengthens, interweaving through their choices made with each passing day. Her apparent nonchalance and unpredictability disrupts the protagonist's impassive flow of life, gradually opening his heart as he discovers and embraces the true meaning of living. [Written by MAL Rewrite]

Known for her semblance to the Sadako character of The Ring series, Sawako Kuronuma is given the nickname "Sadako" and misunderstood to be frightening and malicious like her fictional counterpart, despite having a timid and sweet nature. Longing to make friends and live a normal life, Sawako is naturally drawn to the cheerful and friendly Shouta Kazehaya, the most popular boy in her class. From their first meeting, Sawako has admired Kazehaya's ability to be the center of attention and aspires to be like him. When Kazehaya organizes a test of courage for the entire class and encourages her to attend, Sawako sees this as an opportunity to get along with her classmates, starting with Ayane Yano and Chizuru Yoshida. Through each new encounter and emotion she experiences, Sawako believes that meeting Kazehaya has changed her for the better. Little does Sawako know, her presence has also changed Kazehaya. [Written by MAL Rewrite]

Fourteen-year-old Yukio "Koyuki" Tanaka is a dispirited young boy with no goals in life. However, this all changes when Koyuki saves a strange-looking dog named Beck from being harassed by a group of local kids. The dog's owner, 16-year-old Ryuusuke "Ray" Minami, is an emerging guitarist and the former member of a popular rock band. After Koyuki meets Ray again in a diner, the older boy leads him to his former band's meeting place and dazzles Koyuki with his amazing guitar skills. Slowly becoming interested in the glamour of western rock culture, Koyuki decides to start playing the guitar while helping Ray achieve his dream of leading the ultimate rock band. Together with Ray's younger sister Maho and a few other members, the two boys launch their career into the world of rock by forming a band called BECK. Beck follows the group's struggles and successes as they spread their fame across Japan. [Written by MAL Rewrite]