Similar to many recent bestselling fantasy young adult novels adapted to the big screen, The Mortal Instruments: City of Bones is another story about a 'seemingly ordinary' teen girl learns about her true identity and subsequently trapped in a love triangle (while trying to accept her destiny at the same time) in the midst of an eternal conflict between the supernatural good and evil.

The runes, which seemed to be the source of Nephilims' powers and abilities, were never explicitly explained in the film, leaving the audience to wonder what sort of abilities that each of them will grant to the user.The film didn't even explain what the rune initially drawn by Fray earlier in the film is until you google it online to know what it is**.
Moreover, a lot of things were left unexplained or unresolved throughout the film: what happened to Madame Dorothea (the witch) and why she became a demon, what's Hodge curse actually, what happened to Simon after he's been bitten by vampire, why Fray is said to be more powerful than expected...etc.

Compared with The Twilight Saga or Beautiful Creatures, it's still a watchable film packed with enough suspense and twists in the storyline to satisfy most teenagers (girls mostly) and possibly some general audience.
Rating: 6/10
**Angelic Power: The first and most powerful rune given to Shadowhunters by the Angel Raziel. All Nephilim receive this mark upon initiation and signifies their angelic bond. It is also frequently applied to weapons to imbue them with angelic properties as well as wipe them clean of any demonic traces.