A gang of children wearing hoodies, viciously attack Tommy's heavily pregnant wife, resulting in her death. The baby survives, and Tommy is left to bring her up alone. The traumatic experience has given him severe agoraphobia, and he lives in constant terror and isolation, in the bleakest of urban environments. But the threat is far from over, and soon he has to confront his biggest fear.
The opening grabs your attention and sets the tone for the rest of the film. The setting is incredibly grim. Everything is grey, concrete, hard, cold and hostile. The Citadel of the title is one of three oppressive, monolithic tower blocks. The streets are full of empty houses, with graffiti-covered subterranean walkways. Even the buses - which will only go so far into the estate - are gloomy and cold, and driven by unhelpful, faceless drivers. The infrastructure is failing, the electricity supply, the phone lines, and any resemblance of society.
All of this is filmed using a handheld camera, and the photography is remarkably good. Some ingeniously subtle touches - like the use of reflections - add to the overall sense of unease. The lead actor gives an impressive performance which is strong enough to carry the film. We genuinely feel his fear and his sense of helplessness.
The film gets its horror from tension, atmosphere, occasional violence, and an unrelenting sense of dread. It's easy to class this as "hoodie horror" along the lines of Eden Lake. But that's missing the point really. You could see this as a monster movie with an over-complicated backstory, but it has far more depth and intelligence. This is an exploration of a character's mental breakdown, and their journey in overcoming it. Other themes are explored along the way, such as fatherhood, grief, society and religion.
Citadel is not what you'd call a 'feel good' movie, there's no humour or light relief. At times it's quite a bleak, intense experience. But it completely pulled me in, and gave me a lot to think about. In fact, I found it haunted me over the next couple of days, and it's not often a film does that.