当一本神秘笔记从天而降，普通高中生的人生彻底被改写。《死亡笔记》以惊心动魄的设定展开——少年莱特在校园里捡到一本黑色笔记，随之出现的死神琉克露出狰狞笑容，宣告着这本笔记的恐怖力量：只要知晓对方姓名与长相，就能轻易夺走其生命。
初尝权力滋味的莱特先用笔记处决了校园恶霸，又接连让银行劫匪和杀母仇人暴毙而亡。更令人毛骨悚然的是，他发现自己还能操控将死之人48小时内的行为。当他把这个致命秘密分享给暗恋对象米娅时，这个看似甜美的女孩竟展现出超乎想象的狂热，两人迅速结成"审判者联盟"。
以"基拉"为名的死亡审判在城市蔓延。他们强迫罪犯在临终前写下"基拉"（日语"杀手"的谐音），很快，这个神秘代号被民众奉为清除罪恶的救世主。但莱特逐渐发现，米娅对杀戮的沉迷远超预期，而琉克戏谑的眼神背后似乎藏着更危险的阴谋。
天才侦探L的登场将猫鼠游戏推向高潮。通过分析早期案件，他精准锁定莱特的居住地，更设计让莱特父亲加入调查组作为诱饵。当莱特拒绝弑父时，米娅的愤怒彻底爆发——她暗中屠杀了整个调查组，甚至撕毁笔记页角破坏莱特的救人计划。此刻，曾经亲密的恋人已成生死仇敌。
在摩天轮上的终极对决中，莱特早已预判了所有背叛。他提前在笔记上写下米娅的名字，操纵她在坠亡前烧毁写有自己名字的纸页。更惊人的是，他通过预设死亡指令，让多名罪犯在他昏迷期间继续以基拉之名行动，完美制造不在场证明。当父亲颤抖着质问真相时，莱特坦然承认一切，而暗处窥视的L也终于找到了决定性证据...
影片结尾充满哲学意味：手握笔记残页的L陷入道德困境，而死神琉克的笑声在夜空中回荡。当凡人获得神明的力量，究竟谁在审判谁？这个开放式结局留给观众无尽的思考——关于正义的边界、权力的腐蚀，以及人性最深处的幽暗面。
（以下为中文翻译）
When a mysterious notebook falls from the sky, an ordinary high school student's life is completely rewritten. "Death Note" begins with a heart-stopping premise - the teenager Light picks up a black notebook at school, accompanied by the grinning death god Ryuk who reveals the terrifying power of this notebook: as long as you know the target's name and face, you can easily take their life.
Tasting power for the first time, Light first uses the notebook to execute a school bully, then successively causes a bank robber and his mother's murderer to die suddenly. Even more horrifying, he discovers he can control a dying person's actions for 48 hours. When he shares this deadly secret with his crush Mia, this seemingly sweet girl displays unexpected fanaticism, and the two quickly form a "judges alliance."
Death judgments in the name of "Kira" spread through the city. They force criminals to write "Kira" (a Japanese homophone for "killer") before death, and soon this mysterious code name is worshipped by the public as a savior eliminating evil. But Light gradually realizes Mia's obsession with killing exceeds expectations, while Ryuk's teasing eyes seem to hide more dangerous conspiracies.
The appearance of genius detective L escalates the cat-and-mouse game. Analyzing early cases, he accurately pinpoints Light's residence and designs to have Light's father join the investigation team as bait. When Light refuses to kill his father, Mia's fury erupts completely - she secretly slaughters the entire investigation team, even tearing notebook corners to sabotage Light's rescue plan. At this moment, the once-intimate lovers have become mortal enemies.
In the final confrontation on the Ferris wheel, Light had predicted all betrayals. He previously wrote Mia's name in the notebook, controlling her to burn the page with his name before falling to her death. More astonishingly, through preset death commands, he had multiple criminals continue acting in Kira's name during his coma, perfectly creating an alibi. When his trembling father demands the truth, Light calmly admits everything, while L watching in the shadows finally finds conclusive evidence...
The film's ending is full of philosophical implications: L holding notebook fragments faces a moral dilemma, while Ryuk's laughter echoes in the night sky. When mortals obtain divine power, who exactly is judging whom? This open ending leaves audiences with endless reflections - about the boundaries of justice, the corruption of power, and the darkest depths of human nature.