Ah, another Heir of Fire entry! It's interesting and has a catching element of mystery from the very start. Well done. I don't have too much CC for you (mostly grammar stuff), but here goes:
-In the first chapter, I'd recommend putting commas in the line, "your fault, your fault, your fault..."
-In the last sentence of the first paragraph in chapter two, I think it should be "She had him in her sights."
-Last sentence of 2nd paragraph, "Though, at that moment, that purpose..."
-First sentence of 3rd paragraph, "...as if he had heard something, the girl..."
-Second sentence of 3rd paragraph, "...the giant trunk, she..."
-It's generally not a good idea to add in generalizations that switch into the second person like "you". Maybe you could change it to, "As a general rule, the girl found that if she stayed still enough, she could remain hidden and unseen."
-"Dropping her cloak, she hid her..." I don't get the part about the stiletto behind her back. Was she wearing stilettos? And why is she only hiding one?
-I doubt he would "drop" his sword, even onto a bed of pine needles. Maybe you could have him set it down?
So she killed him with a shoe? Nice. All in all, it's pretty good and well written. Great job and good luck in the competition!