Hannibal Lecter was a psychoanalyst who was himself insane. Lecter did not attack his victims at random- he killed those he considered to be rude, and thought he was doing a public service in the process. His fourth victim was an extremely disturbed millionaire, Mason Verger. Verger was a patient of his, committed to him for molesting small boys. He invited Dr. Lecter to his home where Verger hung himself, and Lecter talked him into cutting his own face off with a piece of glass. Verger survived, but was permanently disfigured, and he swore vengeance against Lecter.
Lecter was imprisoned after he killed and ate fourteen (known) people, earning the epithet "Hannibal the Cannibal." His talents were used by a young FBI criminal psychologist-in-training, Clarice Starling, to track down a similar killer years later. Lecter escaped while being held at a Washington police station, and killed two cops and a medic when he hijacked an ambulance. The fugitive was placed on the FBI's Top Ten Most Wanted List, but it hardly mattered since he had relocated to Rome.
Lecter took a job at a museum in Florence and was identified by a local official named Commander Pazzi. Pazzi learned that Verger had placed a large reward for the capture of Lecter, so he made plans to get to know him. After that, Pazzi planned to hand him over to Verger. At the same time, Clarice was assigned to track Lecter down.
After a few years, Lecter was placed on the Top Ten list once more. Upon learning this, Lecter sent Clarice a letter, saying he looked forward to the next game. Pazzi and two men who worked for Verger attempted to capture Lecter and lost their lives in the process. Lecter then decided to return to America and "come out of retirement," as well as pay a visit to Clarice, who had earned his affections. He called her on her cell phone and led her on a game of tag into a mall. In the midst of this, he was captured by people working for Verger, who took him to Verger's mansion. Verger told Lecter that he wanted him to suffer before he died, by feeding him to wild boars. Clarice rescued him and was shot in the process, but Verger was killed by his own doctor. Lecter gave the doctor permission to blame the crime on himself.
He took Clarice to the beach house of her boss, Paul Krendler (who had suspended her). He captured Krendler and prepared a dinner for the three of them, with the main course being Krendler's own brain, part of which he fed to its owner. Clarice called the police and Lecter knew they'd be there in a few minutes, but Clarice was unwilling to let him go and handcuffed them together. Lecter demanded the key, and when he realized Clarice would not give it to him, he cut off his own left hand with a cleaver and escaped. His current whereabouts are unknown.
Lecter and Clarice ran off together and lived happily ever after.