Even reading the synopsis of Oasis can curl back you lips in concern for how such a film can work. Indeed, the film could have be condemned to the fringes of Korean cinema as melodramatic baloney or even an oddity of slightly offensive filmmaking.

The result is quite the opposite. Hemmed by one of Korea’s finest modern filmmakers and two spellbinding lead performances, Oasis is a film that once watched becomes impossible to forget.

It is about how two marginalised individuals are foully treated by family members that should be protecting them and how they find unlikely support from each other.

Released from prison after serving a sentence for manslaughter, mentally atypical Hong Jong-do (Sol Kyung-gu) seeks out his family in Seoul. After being arrested for failing to pay a restaurant bill, he is reunited with his family, who seem less than ecstatic at his return.

Unable to process social cues, Jong-do seeks out the family of the man he killed in a hit-and-run three years prior, meeting the man’s son and his sister with cerebral palsy Gong-ju (Moon So-ri), who is cared for by neighbours.

The family is horrified that Jong-do would contact them, but he becomes infatuated by Gong-ju, sending her flowers and visiting her during the day. Despite a horrific incident at the start of their relationship, the much-maligned pair begin to spend time together and find solace in each other’s company.

So how do you make a film about a romance between two such people work? And not just work, but be one of your country’s most powerful films ever?

Firstly, Director Lee does not water down the characters or themes. This is a deeply challenging watch, quite often in disorientating ways. We have our moral senses provoked, particularly by Jong-do, who commits horrendous acts as he struggles to understand the world around him.

This is not just about how society treats people like Jong-do and Gong-ju, but in this case how the families treat them. People particularly struggle with Jong-do's behaviour. As his disabilities are not as obvious as Gong-ju's, he is treated with distain and anger, despite demonstrated such clear issues with comprehending social situations.

Then there are the performances, where it is not hyperbole to state the leads are two of the best in Korean cinema history. Particularly impactful are the scenes where Gong-ju's cerebral palsy is removed, a visual dream of her own making, and she is suddenly dancing and interacting with Jong-do.

A key tenant of the romance genre, and our love lives in general, is the concept that you find another person and together you are greater than the sum of your parts.

Despite the social commentary on the treatment of disabled people in the hyper-urbanised bustle of modern Seoul, this is a romance film. When Jong-do and Gong-ju connect, the way they have been marginalised by their own families matters less in each other’s company.

Oasis is sad, powerful, profound, important and quite simply a breath-taking piece of cinema.