"VTuber Legend: How I Went Viral after Forgetting to Turn Off My Stream" centers on Aoi Hoshino, a novice Virtual YouTuber (VTuber) who accidentally leaves her livestream running after a scheduled broadcast. Unaware that her stream is still active, Aoi engages in candid, unfiltered behavior, including venting frustrations about her struggles as a VTuber, making self-deprecating jokes, and showcasing her genuine, unpolished personality. The unplanned stream captures the attention of viewers, who find her authenticity refreshing and relatable, leading to a sudden surge in popularity.

As Aoi’s accidental stream goes viral, she faces both opportunities and challenges. Her newfound fame attracts a larger audience, but it also brings scrutiny and pressure to maintain her "real" persona while navigating the expectations of her growing fanbase. The series explores her efforts to balance her authentic self with the curated image expected of a VTuber, as well as her interactions with fellow VTubers, managers, and fans. Key characters include her supportive but overworked manager, Haruto, and rival VTuber Rina, who initially views Aoi’s rise with skepticism but gradually develops a complex relationship with her.

The narrative delves into the dynamics of online fame, the performative nature of content creation, and the emotional toll of living in the public eye. Aoi’s journey highlights the tension between authenticity and professionalism, as she learns to embrace her unique voice while adapting to the demands of her career. The series also touches on themes of self-discovery, resilience, and the impact of viral moments on personal and professional growth. Through its exploration of the VTuber industry, the story provides insight into the challenges and rewards of digital content creation in a highly competitive and ever-evolving landscape.