The best way I can think to describe Grimm is like a cross between The X-Files and Warehouse 13, But without the Warehouse and without the aliens!
Inspired by Grimm's Fairy tales each episode you meet a new type of human hybrid monster, Homicide Detective Nick Burkhardt (David Giuntoil) has Grimm's in his family history it soon becomes apparent that the fairy tales and myths we hear of now are in fact true but only a significant few have the ability to see what others can not. The Grimm's are protectors from the shape shifting hybrids myths - whatever you want to call them, and in turn they fear them as they cannot altogether hide what they are when in the presence of a Grimm. finding his feet in the ever increasing strangeness, Nick is given a case involving a child kidnapper, and wrongly accuses Monroe.
Monroe (Silas Weir Mitchell) a Blutbud - kinda like a werewolf, he helps Nick and they become good friends, partners of the supernatural world, he advises Nick on what and who he is and helps him fight the 'bad guys'
In truth I feel the series could have been a lot darker and takes to many 'Artistic leaps' But the series is good and worth watching, every episode has a new foe but has the underlining story, I really liked the character Monroe, And by mid season liked Nick Burkhardt - the Grimm
Over all - Yeah there are better TV series out there this is by no means the worst and is thoroughly watchable. The series has been renewed for a second season and I will watch!