As the title says, the first 4 series of Castle were brilliant, 8/10. They were interesting, intriguing, funny, and believable. Then, series 5 happened and it went down hill. A lot of stupid story lines, idiotic episodes, and unreal scenarios. There were a few good episodes, but it lost its focus, only 6/10 for the last 4 series. Hence the 7/10 average.
It's all worth a watch though.
It's all worth a watch though.