When you reveal Black Sails as your agenda, shuffle your deck and cut it into 2 stacks. Then, the opponent to your left chooses one stack to be The Hold, which is out of play. The other stack is your draw deck.
Response: After you win a challenge in which you had at least 1 [Naval] attacker, choose 1 card from The Hold. At the end of the phase, add it to your hand. (Limit once per phase.)