[DS9] Season 2, Episode 8 (Netflix: S2 E8): Necessary Evil
Rating: 4
There are a lot of murder mystery episodes in Star Trek. This might be the best one. This is also probably one of the best episodes that examines Odo, which might be a controversial opinion. The flashbacks in “Necessary Evil” explore a complex, fascinating time in not only Odo’s past, but the station’s past. Watching Odo navigate the muddy morality of life on a Cardassian station, and forming from his circumstances a compelling sense of justice, is extremely rewarding.
–
Read more at Memory Alpha
–
Notes:

This is all connected to a murder investigation from back when the Cardassians had control of the station. Odo “re-examines” the case, by which we mean…

… FLASHBACK. Of Terrok Nor. It’s really cool to see the station under Cardassian control. They explain how Odo became a detective, and in charge of station security.
<Previous Episode——————————————————– Next Episode>