Seriously, this series just gets more addicting with each page! I read both Cold Magic and Cold Fire in one go until four in the morning (yes, I know that sounds crazy, and I've got puffy bloodshot eyes to prove it). 
 Concerning the flow of plot and use of language, this sequel is way better than the first novel (i.e: Cold Magic). Finally, we get to know more about Cat's mysterious heritage, not to mention that her relationship with Vai starts to get... well, much more interesting. 
 In truth, for the most part of Cold Magic, Vai has this 'I-am-Darcy-and-you-folks-are-way-beneath-me' character that really turns me off until the very last pages of Cold Magic when he is revealed as a true romantic through and through (swoon). And he just gets better and better in Cold Fire! 
 Apart from Vai, Bee's strong, loyal character comes into light in Cold Fire too. She is not afraid to speak her mind and I love her the better for it! Bee is really the greatest best friend any girl can dream to have. 
 Cold Fire is truly a vast improvement from Cold Magic, thankfully lacking the latter's cumbersome passages. I really look forward to more Cat and Vai in the near future!