I thought that Naomi to Kanako made a mistake by showing the murder right at the beginning of episode 1. Turns out, it wasn't a mistake because the show does a surprising decent job at two things; Firstly exploring the psychological states of the characters, Kanako with her battered woman syndrome and Naomi as a survival of an abusive father. I love the shaking spoon scene when Kanako confronts the husband.
The second thing that Naomi to Kanako does a good job with is showing how Naomi slowly formulates and executes her plan to kill Kanako's husband. You have funny scenes like a trip looking for a place to bury the body turns into a trip for two best friends reminiscing their past or Naomi panicking right before the deed and Kanako showing her conviction. The devil is in the details and I love the details to Naomi's plans and how she tries to anticipate and solve any problems.
The question is, where does the show go from here? Where will the cat and mouse game with the sister lead us? The audience wants Naomi and Kanako to get away with murder but hopefully there will be an unexpected development in the story.
The directing is just not good enough for Naomi to Kanako to get a must watch but for now, its been a surprising, very watchable 6 episodes.