A girl who’s constantly changing personality suddenly reappears in one of her ex boyfriend’s life during his birthday. 15 years have passed since she has disappeared from him, the man who was planning to move to another city with his wife will now have to face a difficult challenge. This mystery thriller is quite well made and pleasant to watch, without being a masterpiece it involves the viewer in a story that keep you guessing for big part of the film. As the title suggests, what will happen manage to stay unknown for a while, but on the other end as the story progresses, the viewer lose a bit of the initial interest as new details are revealed; it’s not a bad film and it could be suitable for any night, but while the initial concept is pretty good, the development of the story fails to stay on the same level, it includes a cameo with Kathy Bates and Danny Glover which improve a bit the story but overall it’s just a decent thriller that won’t stay in your mind too long after the viewing. A bit unrealistic also, not sure if what is shown in this film could happen in real life but if you like strange mystery stories without questioning too much if it could be applied for real, Joshua Marston’s “Complete Unknown” could be entertaining for a night of “easy” cinema.