Been after a copy of this for ages as it got a very limited release but spotted it as part of the Prime BFI Player subscription - so was it worth the wait? - too bloody right it was.
A real slow burning atmospheric chiller has Tomaz (Secaraueau) a migrant worker in London who we learn in lenthy flashbacks was a soldier in an unnamed European war who undertook a good deed only for it to spiral out if control leaving him wracked with guilt.
The hostel he is living in gets burnt down and he is taken in by a kindly nun (Staunton) who places him with Magda (Juri)as a general handyman as she is looking after her termenially ill mother who lives in the attic.
It soon becomes apparant that there is more going on than at first appears...
That is all I am going to say as you need to experience the rest for yourself - as mentioned it takes its time to build the atmosphere but stick with it as its well worth the payoff.
Excellent cast with a growing sense of dread that can only end one way - 4/5