Because the actress wanted to leave the series. Smart move on her part, the ratings plummeted from over 10 million views to less than 2 last year, and it was cancelled. Nicole knew things were going wrong and made a career choice, simple as that. And man, does it suck to be a fan... this could really have been something great, but... Did you know they never had the same director or writers for 3 episodes in a row? That set must have been insane. Hollywood really knows how to wreck its own art, doesn't it?