Anyone who does not cry during Dear Zachary: A Letter To A Son About His Father is inhuman. There's no way to sit through this movie without - at the very, very least - barely fighting back tears. I was fighting back sobs for the whole last half hour of this documentary. Equal parts inspiring and devastating, Dear Zachary should be advertised as a tear duct cleaner.

It's hard to summarize the movie since it's so many things, and it changes as it goes along. There are also aspects that should not be revealed to anyone before they see the movie - do yourself a favor and stay spoiler free and resist the urge to look up the real case behind the film - which really inform what this movie eventually is about. But it begins simply, and sadly enough: filmmaker Kurt Kuenne sets out to discover everything he didn't know about his best friend, Andrew Bagby, who has been viciously murdered in a park in Pennsylvania. As Kurt travels the world trying to discover the secret sides of this guy he knew since they were children, things get really, really complicated. Andrew's killer, a spurned ex, is revealed to be pregnant with Andrew's child. Kurt's film changes focus - now he's documenting Andrew so that his son will have a chance to know something about the father he'll never meet.

I'm seriously welling up right now writing this. It sounds gimmicky and lame of me, but it's the truth - Dear Zachary is a film that will attach itself to you, that will continue to evoke strong emotions in you long after the movie itself has ended.

Shirley Turner, the crazy who killed Andrew and was pregnant with his baby, fled home to Canada, where a series of judicial boneheaded decisions kept her out on the streets. She gave birth to a boy, Zachary Andrew. Andrew's parents, the unbelievably brave and strong David and Kathleen, left behind their lives in California to move to Canada as Shirley's extradition process wound on and on and on. They wanted to be near their grandson, the last living link they had to their own child, and to win custody of the baby. The twists and turns that happen after that make up the most gut wrenching aspects of the movie, but through it all David and Kathleen stand tall, spending days out with baby Zachary and his mother, the woman who killed their son in cold blood. They put up with the pain and the horror just so they can be near that baby.

That's the inspiration. Hopefully, when everything is said and done and you've wiped the last tear from your cheek, that's what you take home with you - the way that these people, in the face of the most hideous situation and the most terrible adversity, kept on going, kept on trying.

This is where I put on my critic hat. Dear Zachary is moving and will stick with you, but it's also a deeply imperfect film. In many ways it's a cry of anguish from Kuenne, a work of naked grief and anger. He makes some choices that are maudlin or just plain bad, including some over the top music cues and a number of scenes where jarring sound effects detract from the effect he's going for. But you have to forgive it simply because this is an outpouring of pain in cinematic form, a concentrated burst of sadness and hate and anger on celluloid. I actually like that it's imperfect, that Kuenne hasn't gone in and cleaned it up and taken out the bits that are a little hokey or where strings are being pulled a little too hard because it gives the whole work a feeling of serious authenticity. We're watching this filmmaker acheive his catharsis, such as it is, and maybe we're getting a little bit of our own.

Dear Zachary is a tough film, one that left me a wreck and is guaranteed to put you through an emotional wringer, but that shouldn't keep you from seeing it. This is a movie that manages to find hope in the most awful of situations, that connects directly to your humanity. It's a testament to the power of cinema as shared experience as well as being a riveting, shocking story that unfolds around you as you watch. And if you need a good cry, this is the place to get it.

8.5 out of 10