They march the Doctor out to the plank, where he proceeds to mock their pirate laughs and practice diving poses. They don't have much fresh water left, the captain says, so it's bye-bye for the Doctor and Rory. "Take the doxy below and set her to work," he says. I think we can imagine what kind of work they have in mind. Ew. She calls for Rory as one of the pirates drags her away. Rory struggles uselessly against his captor. He tells the pirates that Amy's not a doxy, but Amy was hoping for a stronger defense than that. This is Rory, though, who is only intermittently brave. Below deck, Amy is left alone in order to come up with some bright ideas. Topside, the Doctor is taking an awfully long time on the plank. First he asks for more laughter (which he gets) and then wonders why there are only five crewmen on such a big ship. "I suppose all the rest of them are hiding someplace and they all gonna jump out and shout 'Boo!'" "Boo!" shouts Amy. She's standing behind them, wielding a sword and wearing a coat and a tricorn hat. Congratulations, Amy! You're now the proud owner of a head full of lice. Seriously, people. Do not wear random hats you find lying around on pirate ships. Or anywhere, for that matter.
The pirates are disproportionately afraid of her. The captain puts down his gun when she orders him. The Doctor scolds her. Shut up, Doctor. A couple of the pirates charge at her, swinging with wooden poles. She puts up a decent fight and backs them up against a part of the ship. They're bug-eyed with fright. Amy is quite pleased with herself. Emboldened, she swings the sword and fights off her next attackers. Having watched too many pirate movies, she grabs a length of rope and swings across the deck, nicking one guy across the hand before she lands. "You have killed me," he says. A black spot appears on his palm. Amy thinks he's being a big baby, but the captain explains, "All it takes is one drop of blood and she'll rise out of the ocean." Another pirate advances toward Amy. She takes another swing on the rope, gets grabbed and drops the sword. The blade scratches Rory across the inside of his fingers. A black spot shows on his palm. "She can smell the blood on your skin," the captain explains helpfully. "She's marked you for death." He says there's a demon in the ocean, which delights the Doctor like Easter candy. He's even impressed with how efficient this demon is, giving people a note before it kills them. Yeah, efficient or twisted. Either one.