Castle Season 3 Episode 4 (Castle s03e04) with title “Punked” aired on Monday, October 11th 2010 at 10:00 pm via ABC Network.
Here is summary for Castle Season 3 Episode 4 :

Castle and Beckett look into the murder of a young mathematician gunned down with a 200-year-old bullet, sparking some wild theories by Castle about a time-travelling killer.