Mack Greer (Beverley Mitchell) attends her best friend Heather (Chiara Zanni)'s wedding shower where they have psychic Nadira. During her drive home, she hits a woman. The woman lies dying on the road but then she disappears. Max is a law student studying in an office when she's attacked. She stabs and kills the man but then he disappears too. The cops are tired of her false reports. She goes to a psychiatrist to deal with her father's suicide and her migraines. She goes to Nadira but she's told that there is nothing she could do for her. She investigates and finds that the deaths are actually real. Her father was a photographer who sometimes work with police detective Morgan. Meanwhile Heather's fiancée Evan is Mack's ex and he's still hung up on her. It's a fine supernatural thriller story. The production is pretty weak. The police sometimes look like they're from the 50s. Beverly Mitchell is fair but not great. There is a lack of tension but it is still watchable. It's just not that good.

**SPOILERS** Too overly plotted to really get a grip on "I Know What I Saw" has one sub-plot too many to really understand what it's trying to tell its audience. Were first told that law student Mackenzie Greer has some kind of psychic power where she can see deaths that either already happened or are about to happen. We get a sample of Mackenzie's psychic visions in three different deaths that she in some way was a part of. A young 17 year-old high school student that was killed in a hit and run accident. An office building janitor who was slashed to death and a woman who fell or was pushed to her death from a six story building.These events are obviously conjured up by Mackenzie herself but the policeman investigating her claims Det. Morgan feels that there's something more to them that just Mackenzie's wild imagination. Det. Morgan was involved in investigating a number of murders that were eerily similar to those that Mackenzie is now being haunted by. One of them, the 17 year-old student hit and run accident, he was not only on the scene of the accident but MacKenzie's father Charles Greer a photo journalist was the person who took pictures of the crime scene! It was not long after that that Charles Greer committed suicide!We go through almost the entire film not knowing what exactly Mackenzie Greer's obsessions really are. Were told earlier on that her father's suicide had really screwed up her mind in not only that he killed himself but didn't even bother to leave a suicide note explaining why he did it! Were later given to understand through a medium, Nadira, that Mackenzie gets in contact with that she's being contacted by someone from beyond the grave, her father?, who's trying to keep her out of danger. A danger that she unwittingly got herself into in making public, to the police and newspapers, her strange visions.There's also this off the wall sub-plot about Mackenzie's ex-boyfriend Evan who dropped her for her best friend Heather whom he's since become engaged to. Evan seems likable enough but also seems to be a bit too weird when it come to his ex-girlfriend Mackenzie whom he still, from what we see of his actions, carries a torch for. It's towards the end of the movie that the truth finally comes out about what's been puzzling Mackenzie all throughout the film. That has to do with her fathers, Charles Greer, crime scene photos that he took of the hit and run accident that in fact turned out to be a cold-blooded murder! It's in Mr. Greer's photo, and negatives, that he kept hidden in the liner of his combination lock suitcase that will not only reveal who killed and ran down the young woman but also the other persons, the janitor and lady on the rooftop, who were part of Mackenzie's strange and horrifying visions!