Based on the book... Clary can see things and people that no one else can see and when her mum goes missing she finds out it's because her mum was a warrior who protected the world from demons.
I went to see this film today with two friends and one of my friends had already seen it twice before! We're all reading the books at the moment as well and honestly the film was so much better than I thought it was going to be. It was amazing! You should definitely go and see it!