Castle, Season 2

[Beckett, Ryan, and Esposito are at dead ends in their respective cases]

Beckett:
We'll start over. Fresh eyes. You take our murder, we'll take yours.

Esposito:
All right.

Castle:
[a thought strikes him] Whoa, whoa, whoa, whoa. Say that again.

Beckett:
[confused] "You take our murder, we'll take yours".

Castle:
Could it be that easy? You take mine, I'll take yours.

Esposito:
What are you getting at, Castle?

Castle:
Strangers on a Train.

Ryan:
The Hitchcock movie?

Castle:
I'm partial to the novel by Patricia Highsmith, but yes. We have two strong suspects, but with airtight alibis, right?

Esposito:
Right.

Castle:
We know they're connected. What if the connection is the killers?

Beckett:
Jason and Eric committed each other's murders.

Castle:
And made sure they had an airtight alibi for the murder they knew they'd be suspected of. It's not our victims that are connected, it's our murderers. Crisscross!