And it's remarkable how great acting can transform a competent but mostly unremarkable thriller into something greater. I can't imagine what this movie would look like with anyone but Jodie Foster (possibly America's greatest actress?) in the lead role, and her uneasy chemistry with co-star Terrence Howard really works--in fact, as the sane anchor, I could see the movie failing with a bad performance in his role easier than in her role.
Foster plays a radio show host (an excuse for a little too much lazy pseudo-interior monologue) who is attacked in Central Park at night. Her fiancee is murdered and she's in a coma for three weeks. Trying to re-establish her life, she finds she's afraid of everything, until she buys a gun and becomes an (at first) accidental vigilante. But under the thriller surface, there's an interesting study in how a traumatic event can change you, and specifically the changes that come from the unfeared becoming feared and vice-versa. Pretty interesting, but again it wouldn't work with any lesser actors.