After receiving confidential information regarding weapon-smuggling, Bishop and Torres (Emily Wickersham, Wilmer Valderrama) subsequently become engaged in a deadly shootout in a former sheriff's residence that has been designated a historical site. When events take an unforeseen turn, however, the agents find themselves locked in abandoned jail cells on the premises in the new episode "1mm." Chris Boudreaux guest stars; Mark Harmon and Sean Murray also star.