I vote "Wicked Game" -- that is a part one and a part two.
It is from the TV series Medium and it is a two-parter involving Allison (Patricia Arquette) and the private detective Cynthia (Anjelica Huston) that Allison's working for. The episode begins with Allison dreaming of Susie, a kidnapped girl from years ago. It's Cynthia's daughter and Cynthia's never told Allison that she had a daughter, let alone that her daughter's been missing forever.
Allison sees another young woman with Susie. I should explain Allison is a pyschic for anyone who does not know that. And Susie sees him kill the woman and then manages to escape. But -- Allison is seeing all of this in various dreams -- Susie gets killed by the man who kidnapped her and has been holding her hostage.
Cynthia turns on Allison when it turns out that the woman she saw Susie see killed (the other young woman who was being held hostage with Susie) is alive.
But then it turns out that woman was part of the sick fantasy. That woman was in with the man. They were sick and twisted. They played a little game for their own kicks. And the woman wasn't kidnapped.
Allison and Cynthia figure this out. But they can't figure out how to get the evidence required to convict. Cynthia's daughter is dead. And there's nothing they can do. Allison's at her house near the end of part II and she gets a call from Cynthia asking her to come to the house where the Susie was held. Allison does and it's there that she learns Cynthia has killed the woman. It's the closest to justice Cynthia can get. And Cynthia's called the police who are on their way to arrest her.
It was a really powerful two-parter, well written, full of twists and two of the best actresses to grace television in the last ten years.
You can stream seasons one through six at Netflix. I believe the two-parter I am describing is season five.
This is C.I.'s "Iraq snapshot" for yesterday: