: A criminal named Purcell (played by Dominic Purcell) walks into a police station in Boone, Wisconsin, to confess to a murder he was previously acquitted of on a technicality.

While " Instinct " is the specific title for Warehouse 13, other popular shows have significant 15th episodes in their fourth seasons:

: S4E15 is " The Milk Maker ," where Lisa's motherly instincts are tested by a brood of baby chicks.

: S4E15 is " Glaciator 2 ," featuring major developments in the relationship between Ladybug and Cat Noir.