"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 narrative 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 for exile or death depending on the player's choices.

Determined to avoid her grim fate, Katarina devises strategies to alter the game's predetermined outcomes. She focuses on building positive relationships with the key characters who could influence her destiny, including the game's potential love interests and rivals. These characters include Prince Geordo Stuart, her fiancé and one of the game's main love interests; Alan Stuart, Geordo's twin brother; Keith Claes, her adopted brother; Mary Hunt, a noblewoman and rival for Alan's affection; Sophia Ascart, a shy girl with a mysterious connection to the game; and Nicol Ascart, Sophia's protective older brother.

As Katarina navigates her new life, her efforts to avoid doom inadvertently lead to unexpected outcomes. Her genuine kindness and obliviousness to romantic advances cause many of the characters to develop feelings for her, creating a complex web of relationships. Despite her lack of awareness, Katarina's actions consistently disrupt the original game's narrative, steering events in unpredictable directions. The story balances humor with moments of tension as Katarina works to secure her future while remaining oblivious to the growing affections of those around her.

The manga explores themes of self-determination, friendship, and the consequences of altering fate. Katarina's journey is marked by her relentless optimism and determination to survive, making her a unique protagonist in the isekai genre. The series maintains a lighthearted tone while addressing the stakes of her situation, offering a fresh take on the villainess trope and the dynamics of otome game-inspired narratives.