Since the late 1950s, this spirit has been responsible for many deaths, most of them designed to look like suicide. The spirit was created by a shaman in the countryside, who was paid by a well-to-do family from which Hae-sang is descended to perform a dark ritual that would ensure the family’s prosperity.

The ritual involved the horrific and prolonged sacrifice of a young girl, Lee Mok-dan (Park So-yi), but the shock reveal is that the spirit does not belong to her.

Rather, it belongs to her older sister Lee Hyan-gi (Shim Dal-gi), who was originally selected as the victim. She tricked her sister into taking her place in the ritual when she found out what it involved and realised that she could get some money out of it.

Hyan-gi’s guilt eventually got the better of her but that just ended up with both sisters dying in the ritual. The grudge spirit of Hwan-gi that resulted from the ordeal is formidable to say the least.

In the show’s closing episodes, San-yeong and Hae-sang get closer and closer to discovering the truth and bodies begin to drop like flies as Hyan-gi desperately tries to protect herself and complete her plan.

Among those victims are the faithful and dogged detective Seo Mun-chun (Kim Won-hae), whose death proves to be the turning point for his sceptical partner Hong-se, and Hae-sang’s grandmother Na Byung-hee (Kim Hae-sook), who commissioned the ritual all those years ago.

In her dying moments, Byung-hee stabs at her own fingers to leave Hae-sang a final clue. Whether she does so out of remorse or revenge is a mystery she takes to her grave.

Hyan-gi almost succeeds in her plan as she manages to take over San-yeong’s body completely. San-yeong is shoved into a waking nightmare, living in a mirrored world – somewhat reminiscent of Stranger Things – where she is constantly chased by a spectre with long hair.

During a thrilling climax, Hae-sang manages to get his hands on the only thing that could rid the world of Hyan-gi: the remains of her severed finger. In a final act of desperation, Hyan-gi spitefully threatens to destroy San-yeong’s body, which would end them both.

As she victoriously struts past a mirror, Hyan-gi is suddenly stopped in her tracks. San-yeong has summoned the strength to fight back, and herein lies the message of the show.

San-yeong has lived her entire life for others, whether her mother or all the demanding clients she dealt with during her many service jobs, and in the end that included Hyan-gi, who controls her completely. Realising this in the mirror world, she wonders to herself: “Why and for whom did I mistreat myself so cruelly?”

The spectre chasing her in her nightmare is none other than herself. Once she decides to live for herself she is able to wrest control of her body back from Hyan-gi and destroy her once and for all.

It’s an empowering climax, which works thanks to Kim Tae-ri’s ferocious dual performance and Kim Eun-hee’s careful world-building throughout the series. Nothing ever felt out of place, but now everything connects in this cathartic conclusion.

San-yeong survives, as does Hae-sang, despite a bad stab wound, and San-yeong’s mother Yoon Gyeong-moon (Park Ji-yong), who is almost killed by Hyan-gi twice. Yet Kim Eun-hee adds a dark edge to the show’s seemingly happy ending.

She may now be living for herself, but San-yeong has a condition that is slowly turning her blind. For women in Korea, freedom comes at a cost. No matter what the future may hold, some damage has already been done.

As a result San-yeong is enjoying herself now, aggressively working through bucket-list items with her loved ones. In a country where women, more than men, seem to make the most of what little free time society affords them, this feels like a fitting closing image.

Building and building to an exceptionally strong finale, Revenant proves why Kim Eun-hee is one of the best in the business.

Revenant is streaming on Disney+.