There comes a point during this extraordinary film when you wonder how is this going to end? As 9 then 10 year old Benni (Helena Zengel) is shunted from care home to care home, to lock down to hospital, police intervention, to foster home to mother. All under the care and watch of Mrs Bafané (Gabriela Maria Scheide) who as her social worker has her best interests at heart but is close to breaking point just about coping with almost unimaginable pressures.

Benni has massive difficulties fitting in anywhere having swingeing changes in temperament ranging from just loud and difficult to vandalism and violence – at one point when she returns home of her own volition, she attacks her mother with an ornament during an argument. The triggers are many but because of a childhood trauma she cannot stand anyone touching her face (apart from her mother) as it sets-off an extreme reaction.

The authorities are virtually at their wits end as many care homes just won’t take her and she is too young to be institutionalised. In any case those whom she has let get close see that there is potential for her. As when she returns to her foster home and the joy that has reuniting with Silvia (Victoria Trauttmansdorff) even taking to her current foster child. In contrast to her mother Bianca (Lisa Hagmeister) - whom Benni clearly loves – continually letting her down.

The focus drifts to social worker Micha (Albrecht Schuch) who ostensibly is called on just to escort Benni to school and nothing more. A sort of trust starts to build (there’s a suggestion that he too has had his problems) and Micha suggests taking Benni off for a period to his cabin in the woods away from the world, tv, internet and the like. Nothing sinister just a method that he has used before. It’s partially successful but they establish a bond that Micha has to break and that Benni doesn’t fully understand the limits.

It’s tour-de-force filmmaking with soundtrack, photography and editing all coalescing giving an insight into Benni’s kaleidoscopic mind. It’s very technical filmmaking used to enhance an astonishing, very human, central performance from Helena Zengal. At times sharp as scalpel, blunt as a mallet, as loving as your pet cat but fully capable of unleashing frightening mental and physical barbs.

Nora Fingscheidt’s writing and direction is layered and it’s impossible not to feel sympathy for a child that is just slipping through a system that just doesn’t have the resources to cope. Equally there’s shared frustration with some of her social workers as seemingly everything they try is ferociously thrown back at them.

System Crasher is available on demand now.