"The Garden of Sinners Remix -Gate of seventh heaven-" is a compilation film that re-edits and restructures the original "Kara no Kyoukai" (The Garden of Sinners) film series into a cohesive narrative. The story is set in a world where supernatural phenomena and human psychology intertwine, exploring themes of identity, morality, and the boundaries between life and death. The narrative revolves around Shiki Ryougi, a young woman with a mysterious past and the ability to perceive the "lines of death," which allow her to destroy anything she cuts along those lines. Shiki works alongside Mikiya Kokutou, a kind-hearted and observant man, and Touko Aozaki, a pragmatic and enigmatic mage, to investigate supernatural occurrences.

The plot unfolds non-linearly, with each segment focusing on a specific case or event. These cases often involve individuals grappling with their own psychological struggles, which manifest as supernatural phenomena. Shiki's dual personality, a result of a traumatic childhood incident, adds complexity to her character and her interactions with others. Mikiya serves as a grounding force, offering emotional support and a moral compass, while Touko provides expertise in magecraft and a pragmatic approach to solving problems.

One of the central arcs involves Shiki confronting her own identity and the consequences of her abilities. Her journey is marked by encounters with various antagonists, each representing different facets of human nature and the supernatural. The narrative delves into the philosophical implications of existence, free will, and the nature of evil, often blurring the lines between right and wrong.

The film also revisits key moments from the original series, such as Shiki's confrontation with a serial killer who manipulates time, her battle against a ghostly entity tied to a haunted building, and her struggle with a cult that seeks to transcend human limitations. These events are interwoven with quieter, introspective moments that explore the characters' relationships and personal growth.

"The Garden of Sinners Remix -Gate of seventh heaven-" serves as both an introduction and a retrospective for the series, offering new viewers a streamlined experience while providing long-time fans with a fresh perspective on the story. The film maintains the atmospheric and psychological depth of the original series, emphasizing its intricate plot and complex characters.