Title: The Double Down
Air Date: September 28, 2009 at 12:00 AM PDT
When two separate murders are committed on the same night, Castle makes a wager with Ryan and Esposito that he and Beckett will solve theirs first. The frenzied race to catch their respective killers and win the bet leads each investigative duo to a likely suspect, but these potential perps have airtight alibis. Subsequent twists in both cases force the two teams to work together to unravel the seemingly disconnected murders.