"Moby-Dick" tells the adventures of wandering sailor Ishmael, and his voyage on the whaleship Pequod, commanded by Captain Ahab. Ishmael soon learns that Ahab has one purpose on this voyage: to seek out Moby Dick, a ferocious, enigmatic white sperm whale. In a previous encounter, the whale destroyed Ahab's boat and bit off his leg, which now drives Ahab to take revenge.