Everyone is literally dying of thirst. The Mariner sees another ship's sail at a distance. He wants to yell out, but his mouth is too dry, so he sucks some of his own blood to moisten his lips. He's like, "A ship! We're saved." Sadly, the ship is a ghost ship piloted by two spirits, Death and Life-in-Death, who have to be the last people you'd want to meet on a journey. Everyone on the Mariner's ship dies.