"My Next Life as a Villainess: All Routes Lead to Doom!" is a manga series that adapts the light novel of the same name, blending elements of comedy, romance, and fantasy. The story centers on Katarina Claes, a young noblewoman who regains memories of her past life as a Japanese high school student after hitting her head. In her previous life, she recalls playing a dating simulation game titled "Fortune Lover," in which the character she now embodies, Katarina, is the primary antagonist destined to face dire consequences depending on the player's chosen route—exile, death, or ruin.

Determined to avoid her fate, Katarina devises strategies to alter the game's narrative. She begins by befriending the game's potential love interests, including the kind-hearted prince Geordo Stuart, his protective brother Alan, the studious Keith Claes (her adoptive brother), the reserved Nicol Ascart, and his cheerful sister Sophia. Katarina also forms bonds with the game's protagonist, Maria Campbell, a commoner with light magic abilities, and other key characters like Mary Hunt and Sora Smith. By cultivating genuine relationships and displaying unexpected kindness, Katarina inadvertently shifts the dynamics of the original game, creating new romantic and interpersonal complexities.

The narrative explores Katarina's efforts to navigate her new reality while balancing her noble responsibilities, friendships, and the unintended romantic attention she garners from multiple characters. Her obliviousness to the growing affections of those around her adds a layer of comedic misunderstanding, as she remains focused solely on avoiding her "doom flags." The story progresses through various arcs, including her time at the Magic Academy, where she continues to influence the lives of those around her, often in ways that diverge significantly from the original game's script.

The manga maintains a lighthearted tone, emphasizing Katarina's endearing clumsiness and determination, while also delving into themes of self-improvement, friendship, and the unpredictability of life. The characters' development is central to the plot, with each individual's backstory and motivations explored in ways that enrich the overarching narrative. The series balances humor with moments of emotional depth, creating a engaging and accessible story that appeals to fans of both romance and fantasy genres.