This season marks the first season with Sam Waterston playing the role of executive assistant district attorney Jack McCoy. Jack replaces Michael Moriarty's Ben Stone, who had held the position of lead prosecutor for the first four seasons. Waterston turns out to be a great addition to the cast. It's not that he is better or worse in the role than Moriarty - he's just different. Moriarty's Ben Stone was more of the crusader, where Waterston's Jack McCoy is more out to right specific wrongs rather than "make new law", which was often Stone's objective. Once again the cast has great chemistry. We have what is probably the finest old cop/young cop partnership in the history of TV in Lenny Briscoe and Mike Logan, the two DA's Jack and Claire have great chemistry to the point that you are kept guessing as to whether or not anything more ever goes on between the two of them than just business, S. Epatha Merkerson is commanding and thorough as Lieutenant Van Buren, and then of course there is Steven Hill as the actual elected District Attorney and his memorable one liners and reflections that add just a pinch of needed spice to each episode.
The episodes are of high caliber too. The one that always comes to my mind is "Coma". This is one of the few L&O episodes where the actual murder is solved, but you know there has to be more to the story of what appears to be a murder for hire. Unfortunately, the actual murderer is a pseudo street person who has just died of natural causes when he is found out. The problem is, the husband of the victim is the actual suspect. He is arrogant and extremely guilty looking with the exception of that pesky problem of evidence. This case is revisited in season six. "Performance" is an extremely complex episode when what begins as an investigation into what appears to be an actual murder made into a movie turns into an investigation of an entire social order between teenagers in which boys get points for "conquests" of girls and the girls go along with it so they aren't made outcasts. The excellent "Second Opinion" is the bizarre case of a woman who collapses, and as she is being worked on in the emergency room releases toxic fumes that cause the loss of consciousness of several of the workers there. The case gets traced back to a doctor who is administering an unorthodox treatment for breast cancer. McCoy wants to prosecute, but when he sends Claire out to talk to women who have been patients we see that there are definitely two sides to the story. On one hand, there are all of the women who managed to avoid the scarring and horrors of chemotherapy and seem to be doing very well. However, there is also the fact that Claire can't interview quite a few of the patients because they are deceased. The whole episode brings up the argument of, in such a personal choice, whose decision is it anyway when it comes to the course of treatment to pursue.
"House Counsel", although it seems to be "ripped from the headlines" in the sense that it resembles the case of John Gotti's lawyer being disqualified because he was deemed too involved in Gotti's activities, actually is a pretty original episode. Here we get one of our first looks into the complexity that is Jack McCoy. He prosecutes a defense attorney for conspiracy to commit murder in the case of a juror in a mob trial who was paid off in exchange for voting to acquit the mobster. Later the juror was murdered to make sure he never talked. You're never really sure if McCoy is doing this entirely because he is convinced of the attorney's guilt and complicity, or if it is the result of years of sour grapes because the defense attorney has known McCoy since law school and has always been besting him in and out of court. For that matter, we're not sure McCoy is sure of his own motives either, as he appears to have mixed emotions when he actually wins a conviction against his old schoolmate.
The last episode "Pride" sees the exit of the last original member of the L&O cast (I'm counting the DA from the pilot, Alfred Wentworth). The episode itself is not that memorable except for the fact that at the very end Logan punches a defendant who has just been freed thanks to a deadlocked jury and a controversial topic that was part of his defense. This whole thing with Logan finally resorting to violence seemed a bit contrived. After all, Logan had verbally sparred with suspects before, and taken other cases much more personally than this one, but this is the first time he reacts this way. It results in his demotion and being sent to walk a beat in Staten Island, which is the subject of a later L&O movie, "Exiled". It's been said that the producers of the show decided to get rid of Logan because he was too much like Lenny, but to me this is what made their partnership click so well.
At any rate, this is one of the best all-time seasons of L&O, and I highly recommend it.