They all run to another room on the ship. The Doctor, of course, is now wearing Leechy's hat. Bleh! The Doctor sonics the hat, but it's too late. His copious hair is now riddled with vermin. He theorizes that the Siren is using the water as some sort of portal. In the background, Rory is waxing poetic about the Siren's eyes, which annoys Amy. They decide the driest and safest place to go is the ship's magazine, where all the gunpowder is stored. On the way, the Doctor shouts, "Don't anybody touch anything sharp!" Luckily, all Amy is touching at the moment is Rory. When they get to the magazine, they find the door already unlocked. A child coughs from somewhere inside. The captain pulls a shaggy little moppet out from one of the powder barrels. It turns out the cute little plot device is his son.
They all have a sit-down in the magazine. "What in God's name possessed you, boy? Your mother will be searching for you," says the captain. The boy looks slightly sad. Mom died last winter of a fever. "She told me all about you," he says, perking up. "How you were a captain in the navy - an honorable man, she said." Captain Pirateface looks ashamed, as do the other pirates. They're very sensitive. The captain warns the boy about the monster who's been marking his men for death. The boy coughs and shows them the black mark on his palm. He has no wounds. The Doctor and the grownups have a confab and decide the Siren isn't drawn just to blood, but to the weak and sick, like a hunter looking for prey. The Doctor wants to get everyone to the TARDIS but the captain pulls both rank and a gun on him. Yes, shoot someone in a room full of gunpowder. Brilliant! While they're not looking, Moppet opens up the water barrel for a drink. What's it doing in the magazine, the one room they'd want kept dry? The Siren shrieks and flails her arm out of the barrel. The Doctor shuts the barrel right quick and defers to the captain for a plan. The captain gives his mermaid charm to Moppet and heads off with the Doctor.