THIS POST CONTAINS SPOILERS AND FUTURE SPOILERS!
The Episode starts off with a good CGI Shot of the ship on the sea, people are sailing towards it, turns out they've been out to retrieve something, but return with nothing, they then discuss that they are dead men now, the captain orders them not to go out, but they ignore him, and go out, he puts a keyring on the door, it shows a mermaid, they then hear the man scream out, they then leave the cabin, and notice the man has gone, with no signs of a struggle, then then hear a bang, the doctor, Amy and Rory are in the crate "yo-ho-ho!"
They are then questioned by the captian of the ship, he orders the doctor to be sent of the plank, some funny banter happens between him and the doctor with the differance of not understanding what he's saying because of the time era they are in. Amy is then sent down to the bottom of the ship, and Amy pops out with a cutlass and starts to fight the pirate. Amy then cuts one of the mens fingers, and they warn her that the demon shall come, Amy then chucks the sword, but it catches Rorys hand, he gets a black spot like the rest of them do once she can smell there blood. 2 of the men are killed by the Sirens touch, if they touch anyone they instantly die, so Amy trys to stop Rory touching the Siren, Amy trys to tell the Siren off, she turns from red to green and flings Amy back.
They all work out that it is water that allows the Siren to enter the ship, they find out that the Captains son has been hiding away on board, and that he also had a black spot on his hand, The doctor and the captain go into the TARDIS, he explains quite alot about how it works. The TARDIS Then leaves off on its own, as if another force is controlling it, The doctor then is left without His TARDIS, he then also realises that its not water that lets the Siren in, its reflections, of anything thats polished, anything that acts as a mirror. The Captain and his son have a nice little chat about why he actually became a pirate, The eye patch woman then appears through the wall, she quotes "Your mine, all mine, just stay calm", Amy then notices and wakes up and looks. It then cuts to the doctor and Captain talking about how he got to have very little in life,
the doctor then enters the cabin and sees something staring at him in the face, he cant put his finger on what it actually is, they then have to set sail, they siren then appears out of the crown, it then captures his son, Rory then falls into the water, and the doctor allows the siren to take Rory, to stop him from dieing. The doctor and the crew then agree to allow the siren to take them, to find out what they are doing, They then get transported to another ship, at the same point, and they work out the reflections act as a gateway to another world, the ship appears to not be the sirens, to be some sort of Minotaur creatures, The doctor then touches some alien bogeys, and wipes it on Amy's arm, they then go to another room, to see all the crew are hooked up to some sort of machinery, including the TARDIS, they then set of an alarm, the Siren then appears to float down and look over at Rorys body, she sings to her, and calms her down. The Captain then fires a trigger on the Siren, it turns red and evil, it turns out that the Siren is a virtual doctor, not a monster, Rory cant be set free without him Amy saving him in some way or form, by CPR or mouth to mouth, and Rory lets her, gives her his consent to do so, to risk his life, the captain then decided to stay with his son, They then take Rory back into the TARDIS, Amy attempts to give him CPR, but he doesn't seem to be having any vital signs. She keeps trying but nothing is working. Rory is dead.....
.... Until he suddenly coughs out some water, and it turns out he will be fine, that Amy has saved his life... and he wont have died for the 4th time....
It then shows captain and his son, flying the spaceship, with all his crew supporting them, they fly into the Sirius solar system.
Amy and Rory then go to bed, they think about telling the doctor about his death, then he does another test on Amy, and says, Oh Amelia.