There's a few obvious downsides to living in a sizeable, spacious apartment, particularly if you're in a slightly tender emotional state. The creaking of floorboards or the banging of a carelessly unsecured window in the wind could take root in your mind as an intruder, for instance. That's what happens to Felix (Andoni Gracia), an architect recently split from his girlfriend Vera (M?nica L?pez), as he becomes increasingly convinced that either someone is living in the shadows of his house, or that he's losing his mind.

So far, so 'descent into madness' boilerplate. Things take a more innovative turn when Felix actually captures someone in his house, locking them in an attic and fleeing the house to leave the stranger to die in his own time. But where to live while starvation, dehydration take their course? And, well, that bullet wound probably won't help much either. The obvious solution to Felix's accommodation issues is, obviously, to hide in the shadows of his neighbour Claudia (also M?nica L?pez. Cost effective casting.)'s home. Obviously.

This all sounds a little knowingly ironic, and indeed it does turn into something resembling a Wildean farce with carefully staged scenes of Claudia entering a room just as Felix leaves and such silly contrivances. Despite this essentially turning into an extreme form of stalking, it all becomes rather good natured, or at least as close to it as possible given the nature of what's going on. By virtue of his unique position to eavesdrop, Felix finds himself on the periphery of another unfolding drama, with Claudia's husband Martin having disappeared, following their relationship taking a nose dive not long after the accident that left Claudia wheelchair bound. Come to think of it, why has Martin had the basement locked up and out of bounds for so long? What's he been up to down there?

Quite the oddity, at least as conventional thrillers go. It's quirky, but for once we don't have to use 'quirky' as a synonym for 'rubbish'. As you can probably gather from the above, it's a good distance too contrived to come within barge pole distance of believable. This isn't to say it's not enjoyable, with a standout performance from Gracia that keeps sympathies with him despite his foibles, with Lopez also proving convincing in her dual roles.

This mid-film change of pace provides some clever, and frequently amusing moments, but rather puts the kibosh on the nicely suspenseful paranoia it had been building up until that point. If you want to be critical, and I suppose that's sort of our job, then you could say that this touch of multiple personality disorder dilutes the impact of the film, even if the intruder/intruded role reversal is little short of inspired. Normally, it's at this point I get all sulky, moaning about the thriller portions not being thrilling enough, undermined by the light hearted moments of farce that aren't substantial enough to warrant the change of tone.

However, I don't think I will say all of that, although you'll have to bear in mind that they're perfectly valid points. The nice thing about The Uncertain Guest is that, almost in spite of itself, it works. It's no Hitchcockian masterpiece of mystery and suspense, but it seems to have made its peace with that. The moments of playfulness allow it a goodly bit of leeway so that even though you might see the ending coming from some distance away, it's such an enjoyable journey that it's less of a concern than would otherwise be the case. Good fun all round.

Were I in the business of passing quantifiable judgements, I'd award this 4/5 TippyMarks.