John Ruby

When a bomb explodes at a rally, Castle & Beckett realize to solve the case they must reconstruct the 47 seconds prior to the explosion.

Jules starts to question her relationship with Grayson; Travis' girlfriend throws Bobby off his golf game.

Sounding. As Ava goes on the run to keep from being identified as an informant, Boyd embarks on a risky plan to bring down Markham and his pot farming plans.

Alex offers to design a dress for Jane for a charity event; Penny helps Max baby-sit; Dave and Brad realize their new friendship with the mailman isn't all it was cracked up to be.

When the CSI team works two separate investigations, one involving a woman found murdered in Mexico and another of a local couple found dead in their driveway, they find that the evidence in one case may help the other.

The investigation of a lab tech's murder reveals strange similarities to a cold case from the 1950s; the team catches a glimpse of what goes on in the lab.