I'm not sure how much I can comment on the episode since I don't really know what happened. I was falling in and out of sleep while watching (don't worry, I stopped the show before falling asleep), so I'm probably couldn't repeat exactly how the crime solving went down.
It was nice seeing Captain Montgomery finally get in on the action. Up until now, he's been primarily a side character not really doing anything. This week's episode went in a weird direction from the initial bike incident all the way to the seedy world of the rich and powerful where they dug out lots of dirt.
Castle probably has the most family interaction out of all crime procedurals currently on television. Quite a bit of time was dedicated to Martha figuring out MyFace and uploading an old photo which looks much better than she does now. Castle is very unique in that respect, but it doesn't necessarily bring in the viewers. I know people like this aspect, but no one is really ecstatic about it.