A pair of 11 year-old girls kidnap and ultimately murder a baby. Seven years later they are both released from juvenile hall. One of them, the moody and withdrawn Ronnie (Dakota Fanning), keeps her head down while working at a local bagel shop. The other, Alice (Danielle Macdonald), has continued to protest her innocence and struggles to find employment while living with her frustrated, overbearing mother Helen (Diane Lane). When a toddler disappears – a three year-old girl with a striking similarity to the baby Alice and Ronnie murdered – both young women fall under suspicion for the new crime.

Every Secret Thing marks the narrative feature debut of the hugely acclaimed documentary filmmaker Amy Berg, whose previous works include West of Memphis (2012) and the Oscar-nominated Deliver Us From Evil (2006). The source material, a 2004 crime novel by Laura Lippman, seems perfect territory for Berg. It contains murder and kidnapping, small town distrust, criminal investigations and competing accounts of what crimes occurred and who committed them. Berg has also assembled a solid cast of actors including Diane Lane, Dakota Fanning and Elizabeth Banks. The screenplay is by Nicole Holofcener, herself an accomplished director of several films including Walking and Talking (1996) – a small-scale comedy-drama that I enjoyed a great deal.

I am aware I am over-egging this. The problem with Every Secret Thing is not that it is a bad film per se – in fact it is a relatively solid one – but that with a top flight rank of talent making it, I expected something much, much better. Instead the film is relatively ordinary. The ingredient are all there, but it has been incorrectly baked.

The biggest problem is with the pace and the tension. It is a remarkably sedate film, and it focuses on subject matter that should be riveting. A young child has been kidnapped. There are two teenage suspects, and one or the other may have committed the crime but there is also the genuine possibility that they had nothing to do with it. Time is running out. The audience should be on the edge of its seat, but instead the film takes a very flat, functional approach that lets all of that tension and suspense simply boil away. Perhaps it is Berg’s background as a documentarian simply has not prepared her to direct a dramatic feature. Perhaps Holofcener’s screenplay fails to drill down to the key driving elements. Personally I think it may be a combination of both.

This is a great pity because there is some exceptional character work being done here. Elizabeth Banks successfully plays against type as the quiet, haunted police detective Nancy Porter. Seven years earlier she made her career catching Ronnie and Alice. Now she is forced to consider the possibility they may have kidnapped another child. Diane Lane is particularly good as Helen Manning. She is a complex character, and one whose personality and choices become more and more inexplicable as the film goes on. She forced her daughter Alice to befriend Ronnie, a girl from a deeply impoverished family, and then seemed to like Ronnie more than Alice. Even after Ronnie has led Alice to commit a murder, she still seems to prefer Ronnie – asking after her well being while chiding her daughter for failing to find a job. Lane drills deep into this character to make her easily the most interesting thing in the film. Dakota Fanning is an excellent actor and also does good work here, but Ronnie is ultimately a supporting character. There simply is not enough here for Fanning to do.

Front and centre is Australian Danielle Macdonald as Alice. Like her co-stars she plays an unexpectedly complex character. In some scenes she seems naive, and in others a little too aware and manipulative. Throughout the film it is a little difficult to get a proper read on her. It is a competent performance, but Macdonald’s lack of experience compared to her co-stars does seem to stand out a little.

Every Secret Thing is a watchable film, but it is not a great one – and it is frustrating because there is plenty here that could be great given a little more urgency and polish. I hope Amy Berg gets another chance soon. There is the foundation of something here. I would love to her see really work at a second dramatic feature and produce something that fulfils the potential that glimmers here.