"Ressentiment" is a psychological thriller manga that explores themes of guilt, revenge, and the complexities of human morality. The narrative centers on a young man named Shougo, who becomes entangled in a web of deceit and violence after a traumatic event from his past resurfaces. Shougo, once a promising student with a bright future, is haunted by the memory of a childhood friend, Rina, who was brutally murdered. The incident left him scarred, both emotionally and psychologically, and he struggles to move on from the guilt of not being able to save her.

Years later, Shougo encounters a mysterious woman named Aya, who bears an uncanny resemblance to Rina. Aya claims to know the truth about Rina’s death and offers Shougo a chance to uncover the real culprits behind the crime. As Shougo delves deeper into the investigation, he discovers that the murder was part of a larger conspiracy involving powerful individuals who will stop at nothing to protect their secrets. The story takes a dark turn as Shougo is forced to confront his own inner demons and make morally ambiguous choices in his quest for justice.

The manga intricately weaves together multiple timelines, revealing fragments of Shougo’s past and the events leading up to Rina’s death. Key characters include Shougo’s childhood friend, Kaito, who becomes an unexpected ally in the investigation, and a shadowy figure known only as "The Puppeteer," who manipulates events from behind the scenes. Aya’s true motives remain ambiguous throughout much of the story, adding layers of tension and unpredictability to the plot.

As the narrative progresses, Shougo’s pursuit of the truth becomes increasingly perilous, blurring the line between victim and perpetrator. The story raises questions about the nature of justice and whether revenge can ever truly bring closure. The manga’s pacing is deliberate, with each chapter building suspense and deepening the psychological stakes. By the end, the characters are forced to confront the consequences of their actions, leaving readers with a haunting exploration of the human psyche and the destructive power of unresolved resentment.