"Red Garden" is a supernatural mystery anime set in modern-day New York City, specifically on Roosevelt Island. The story revolves around four high school girls—Kate, Rachel, Rose, and Claire—who attend the same prestigious academy. One morning, they awaken with no memory of the previous night and soon discover that they have died and been resurrected. This revelation comes when they are confronted by a mysterious man named Lula, who informs them that they must fight and kill monstrous creatures to survive. These creatures, known as "Animus," are linked to their deaths and the supernatural forces at play.

As the series progresses, the girls struggle to balance their ordinary lives with their new, gruesome reality. Each character grapples with personal challenges: Kate deals with family expectations and her privileged upbringing, Rachel faces issues of identity and self-worth, Rose copes with her insecurities and relationships, and Claire wrestles with her rebellious nature and strained family ties. Their shared predicament forces them to rely on one another, forming an uneasy alliance as they uncover the truth behind their deaths and the sinister forces manipulating them.

The narrative delves into themes of identity, mortality, and the bonds of friendship, as the girls confront not only the Animus but also their own fears and insecurities. The story takes a darker turn as they learn about the existence of a secretive organization, the "Foundation," which is connected to their resurrection and the supernatural events unfolding around them. The Foundation's motives remain ambiguous, adding layers of intrigue and tension to the plot.

Throughout the series, the girls face increasingly dangerous battles with the Animus, each encounter revealing more about the nature of their resurrection and the price they must pay for their second chance at life. The story builds toward a climactic confrontation that tests their resolve and forces them to make difficult choices about their futures. "Red Garden" blends elements of horror, drama, and action, creating a compelling narrative that explores the psychological and emotional toll of its characters' extraordinary circumstances.