Haha! This was great. I've only read the first Dresden book, but the voice seemed great to me, and all the Castle stuff was spot-on. Laughed out loud at your description of Ryan, especially this: "He has a tendency to wear an expression that is a combination of puppy dog and ‘your call is very important to us’ and that makes you want to tell him things." Also loved the line “Or they would combine and form a super-cop greater than us all."

I've read another Dresden Files/Castle crossover and I have to say, those universes work well together—not just the crime elements, but the characters. Would love to see you write more! :-D