THE SOVIET SECRET ASSASSIN ON CASTLE'S TURF! Back when BUCKY BARNES was a mind-controlled sleeper agent, he was deployed for secret missions of political importance. But when he's unleashed in New York City, whose target will end up dead — WINTER SOLDIER's or PUNISHER's? The Punisher's one-man war on the guilty crosses paths with other denizens of the Marvel Universe with explosive and unexpected results in THE PUNISHER SHOWDOWNS! RATED PARENTAL ADVISORY.