It was heartbreaking that Beckett was so close to finding her answers, only to lose it.

There has to be other evidence somewhere indicating why someone hired a hit man to kill her mother. They just need to find it, and put that puzzle together. But I expect no more major developments on that front until next season.

It was also great to see this new milestone in the relationship between Castle and Beckett--he felt humbled enough to want to leave their partnership, and she admitted that she likes him enough to want him to stay. It's not romance (yet), which is good. But it's finally genuine friendship.

Overall, it was a good mystery with compelling emotional ups and downs.