I thought this one was great. The case was excellent, with some good evidence collecting and processing, and to kill off a season 3 regular, well, I wasn't expecting that. What was different about this one was that it had a lot of character moments which were not confined to this episode. Something that is rare for this show. It tends to usually focus on one episode at a time, and viewers could watch them in any order and still be in on the story. But Catherine found out who her true father was, which i'm sure will affect episodes to come and Grissom is fixing his hearing, which was a major story arc from the second and third seasons. It will be interesting to see the continuation into season four and if these events will have any impact on the future. But all round, a brilliant episode. 9.5/10
This is my 6th review.