University students Yuri (Mizuki Yamamoto) and Natsumi (Aimi Satsukawa) watch a cursed videotape and find themselves both fated to die at the hands of the violent spirit Sadako. Across town high schooler Suzuka (Tina Tamashiro) is haunted by the vengeful ghost Kayoko that hides inside a house with a long history of violent murder. When their nightmares collide, the two spirits will go head-to-head for the souls of their victims.

When Japanese film horror broke internationally in the early 2000s, it was largely on the back of two films: Hideo Nakata’s Ring and Takashi Shimizu’s Ju-On: The Grudge. Both were ultimately remade by Hollywood, as well as each developing a long string of sequels (Ring led to four sequels in Japan, The Grudge – already the third in its series – to another five). Each focused on a particular ghostly apparition. In Ring it was Sadako, a young psychic that was murdered and thrown down a well only to return in viral form via a cursed videotape. For The Grudge it was Kayako, a white-skinned dead woman whose voice rattles like a creaky door and who murders any intruders to her house. To be honest both franchises have felt fairly worn-out of late, and are hitting the point where combining them together in a King Kong vs Godzilla-style smackdown is not the worst possible idea in the world. If nothing else it is a solid excuse for a deliberately silly and over-the-top exercise in nostalgia and parody.

Sadly director Koji Shiraishi takes an overly reverent route, and that pretty much kills Sadako vs Kayako in its tracks. The overwhelming majority of the film is taken up by establishing the two supernatural forces and easing its protagonist into their respective curses. It is a bizarre waste of the audience’s time, since one can reasonably expect anybody tempted to watch the film will already be well familiar with Ring and Ju-On and their respective set-ups and rules. Curiously in the case of Sadako the film simplifies and weakens the Ring mythology. Instead of waiting seven days to die, victims have just 48 hours. The standard escape of showing a second person the cursed videotape and passing the curse onto them is also waved away as an urban myth. Sadako and Kayako both still look great – they’re both heavily derived from Japanese folklore – but they are given very little to do.

The film’s one major innovation is the introduction of Keizo (Masanobu Ando) and Tamao (Mai Kikuchi), a pair of cynical ghost-hunters who hatch a plan to save all three girls by pitting the titular monsters against one another. They feel like anime characters translated to live-action – he’s all cool machismo and black suits, while she is a blind child dressed entirely in red – and while they entertain in fits and starts they never match the serious tone that Shiraishi adopts.

By the time the two ghosts actually interact the film is already almost 90 minutes in. The remaining 10 minutes present a horror climax that does work in fits and starts, but which also ends on a note so open it is as if the film doesn’t actually conclude at all. Viewers would be right to feel more than a little cheated.

An opportunity to have some ridiculous self-aware fun has been missed, and with such a long build-up to such an unsatisfying finale Sadako vs Kayako winds up both a creative dead-end and a huge disappointment. Hopefully both characters will be retired for a while until some enterprising filmmaker can develop a stronger angle for each.