While out looking for an inebriated Barney on the day of the wedding, Robin and Ted reminisce about past relationships. Meanwhile, Marshall and Lily finally resolve their issues and Barney befriends two young guys eager to meet women.
It's literally a race against the clock for the BAU to capture the vigilantes behind a series of attacks taking place every 27 minutes in the nation's capital. Prentiss and Unit Chief Andrew Mendoza lead the effort to identify the Unsubs and what's motivating them.
Wade's dad asks Zoe for help with his love life, but Wade advises her against it. Lavon finds himself in competition with his rival, Mayor Gainey.
After a 50-year-old tape recording left by a murder victim is found, the NCIS team tries to exonerate Ray Jennings (Charlie Robinson), the Marine serving a life sentence for the crime.
A nefarious virus is uploaded to Walter's computer, turning the team's new "smart" building project into a death trap with people locked inside.
