The beginning of the 5th season is somewhat of a hit and miss. CSI (Las Vegas) is the original CSI show with William Petersen as Gil Grissom the lead character. While a number of loner storylines progress there are two very interesting episodes. Down the Drain shows how a set of bones found in a storm drain results in the team finding a house filled with explosives.
Then there is Mea Culpa where after evidence changes in a murder case resulting in the team becoming under investigation. 5.1 provides a lot of entertainment value and is worth a look to solid fans of the show. It can also act as a starting point for new ones. There are the usual few episodes that are not worthwhile though so a word of warning should be given. DVD extras include the standard commentary tracks minus key cast members.