In a contemporary Japanese city where the justice system feels imperfect, a college student named Light Yagami discovers a supernatural black notebook, the Death Note, dropped by a bored Shinigami (death god) named Ryuk. The notebook’s rules state that by writing a person's name while picturing their face, the writer can kill them. Unlike the genius prodigy of the original manga, this Light is portrayed as an average university student working a part-time job, who initially reacts with horror and guilt after his first use of the notebook. However, he soon resolves to use his power to rid the world of criminals, becoming a vigilante known to the public as Kira.

As the unexplained deaths of criminals rise globally, authorities turn to the enigmatic and world-renowned detective L, played with a notably more conventional and handsome appearance than previous adaptations, though he is constantly seen drinking from energy drink pouches instead of eating sweets. L quickly deduces that Kira is a student in Japan’s Kanto region and initiates a high-stakes psychological battle with Light. The series introduces the successors Near and Mello much earlier than the original story, with Near engaging in regular contact with L and a version of Mello existing as a puppet carried and voiced by Near, adding a unique psychological layer to the investigation.

The cat-and-mouse game escalates as Light joins the Japanese police task force investigating Kira, putting him in direct proximity to L. A major divergence occurs with the introduction of Misa Amane, here depicted as a popular pop idol who becomes a devoted follower of Kira. Her dynamic with Light is altered; Light genuinely attends her concerts and uses the Death Note to kill her parents' murderer, making their relationship more reciprocated than in other versions. When Misa acquires the Shinigami Eyes from Ryuk, which allow her to kill by knowing only a face, she recognizes Light as Kira and pledges herself to his cause. The drama weaves in original characters and subplots, such as Light’s mother having died prior to the series, shaping his family dynamic, and the prosecutor Teru Mikami appearing early to handle Misa’s legal cases.

The narrative culminates in a tense confrontation between Light, L, and Near. The drama expands on the intellectual rivalry, forcing Light to adapt his strategies against two formidable opponents from Wammy's House. In the final episodes, the complex plans to expose Kira come to a head, leading to a resolution that redefines the classic ending of the franchise. Following the conclusion of the 11-episode series, the story continued in the sequel film Death Note: Light Up the NEW World, which was preceded by a three-episode web series titled Death Note: New Generation that bridges the gap between the drama and the movie, focusing on new characters investigating a post-Kira world. A separate live-action series adaptation by the creators of Stranger Things has also been announced for Netflix, indicating ongoing Western interest in the property.