If someone were to ask me what Luna is about and expect a quick tagline like, for example "Sandman meets The A-team", they would probably be disappointed with my response. It's a difficult film to sum up in a catchy phrase or even categorize in a genre. In spite of this, here is my ill-advised summary of Luna: Two couples meet at a remote house for a weekend, during which unresolved grievances and mourning mix in a mesh of fantasy and reality. The failure of that last sentence to communicate anything useful is indicative of Luna's vision. There is no tidy box you can lock it away in and move on.

At its heart, Luna is a film about grief and loss, and the ghosts they create. Grant and Christine meet with old friend Dean and his recent wife Fraya after years of estrangement. The reason for their distance is soon revealed: Grant and Christine lost their child years earlier. It's a heavy note to start a film on, but what follows is more than a simple study of grief. As the attempt at a lovely weekend derails, memories and emotions surface, and with them so do spirits who haunt the isolated home. Yes that's right, the characters in Luna occupy a kind of "haunted house", but similarities with the Poltergeist series end there. The house is not haunted by malicious poltergeists, but rather the lost dreams and lingering demons of its guests. These often appear personified as woodland sprites or malignant monsters, haunting the chambers of a character's mind and likewise the house itself.

The images in Luna are vivid, painterly compositions, rich with meaning. McKean uses symbolism in the classical art sense, but without using any classical art symbols. The imagery is far too personal for that. On first viewing, some of the images may seem esoteric. However, on second viewing, a distinct language emerges early in the film, and fluency soon follows. The film's symbolism works within the context of the world it inhabits, like logic within a dream.

Of course, Luna's visual lustre would count for nothing without capable acting to carry the considerable dramatic weight. All four lead actors achieve this with nuanced, personal performances, often read through lingering close-ups. For example, during the scene in which Grant (Ben Daniels) drunkenly argues the role of fantasy, the disdain in his eyes is piercing. The performances give tangible weight to the baggage these old friends carry between them.

Luna is a unique work of cinema, and as is often the case with films like this, it's impossible to say who will or won't like it. Personally, I was fully engaged until the credits rolled, then found the film haunting my thoughts for days after. McKean has a distinct voice in the medium of film, separate from his illustration and graphic novel work; I can only hope we hear more of it soon.

For his third feature after Mirrormask and The Gospel of Us, renowned artist Dave McKean invites us to a cottage where grief, the past and magic all collide. This labour of love was filmed on location on the rugged North Devonshire coast seven years ago just before the investment collapsed. McKean has spent the intervening years working on the CGI, soundtrack and pickups.

For those familiar with the artist's work in illustrating the seminal Arkham Asylum and the covers for the run of Neil Gaiman's Sandman, he again delivers his unique vision of long-limbed, warped fantasy characters, adorned with horns and not-quite faces. Designed, written, directed, co-scored and more by McKean, this truly is a labour of love. The plot follows an estranged couple coming to terms with a personal loss, trying to find some diversion by visiting a mutual friend and his young partner (Defiance and Mirrormask's Stephanie Leonidas). But the past has a way of catching up with you, and as secrets are revealed, home truths open the superficial cracks in the relationships. And that's where the fantasy comes to play.

McKean is working to the maxim 'write what you know about', basing the story in part on the experiences of a personal friend. By making the central male characters (Michael Maloney and Ben Daniels) old art school buddies he also gives himself permission to decorate the home with relevant paintings and sketches and maybe giving voice to some of his own personal views on the abuse of art? Deliberately ambiguous, a rationalist might claim that the fantasy elements can be explained as fever dreams or drunken deliriums. But what about that mysterious doctor? Is it just a magical weekend of Luna-cy?

A thought-provoking film, and a pleasure to watch. The acting feels very genuine. The production might come across to many as rather too 'luvvie', but if you bear with it, the film has a lot to say about life. Stick with it - through the weird stuff - and you'll come out the other side feeling your time has been well spent.