Book 10 opens with a discussion of the "infinite abyss" . The narrator tells us that no one has yet combed this part of the ocean, and that it's too dangerous for humans to venture into it. He tells the audience that he'll call a retired marine biologist to see if he can identify the whale that's swimming in the abyss. He says that the whale's skin and flesh are dark, its dorsal fin is too big, and its teeth on its lower jaw are too soft. He's not sure if the whale is a whale or not, but he's determined to find out. Tommy suggests that they try to get out of the way of the whale, but Tommo says that he can't because the whale keeps shaking them. Tommo points out that if they don't do something, the whale will damage the ship's docking gear, which means that Tommo will have to starve to death. He doesn't want to do that, he says, because he'd rather die than have to live on a stomach full of mercury. He also notes that the meg's response to a signal from the whale was very strong, so they should be able to hear it. They need to get down to the bottom of the abyss and figure out a way to get there.