The Simpsons received the shocking news from the TV shortly after returning from Sunday worship services.

"This is Kent Brockman. Police yesterday arrested Nobel prize-winning scientist John Frink on suspicion of having programmed a robot to murder Antonio 'Fat Tony' D'Amico and whatever the heck Snake's real name is."

"No!" exclaimed Lisa in horror. "I can't believe it!"

"Police claim that they followed the robot to a warehouse belonging to Frink after it attempted to kill Robert 'Sideshow Bob' Terwilliger, former sidekick to Krusty the Clown," Brockman continued.

"Lisa, what's the matter?" asked Marge when she beheld her daughter's morose expression.

"Professor Frink is one of my heroes," she said disappointedly. "How could such a brilliant man be a murderer?"

"Aw, I knew he was evil all along," boasted Bart.

"Shut up!" Lisa snapped. "Remember how you felt when Krusty was framed for robbing the Kwik-E-Mart? I feel ten times as bad right now. So don't push me, or I'll do something you'll regret."

----

Lisa's sorrows hadn't abated by the time she went to school on Monday morning. Miss Hoover noticed her downcast eyes and constant sighing, and asked to know what was wrong.

"My faith in science has been crushed beyond repair," was Lisa's response. "My faith in humanity has been seriously injured, but should make a full recovery."

In front of her desk, classmates Janey and Ralph tried to brighten her spirits with a little pantomime.

"I'm a killer robot," said Janey, shuffling mechanically with her hands outstretched. "Crush...kill...destroy..."

"I'm a victim," said Ralph as Janey wrapped her fingers around his neck. "I'm dying...I'm dead...I'm dying..."

"Knock it off, you cretins," Lisa groused.

The class session commenced, and Alison Taylor stood to deliver her science report. "I was going to speak about Professor Frink's latest invention, the enlarging laser," she told the class. "However, in light of recent events, I chose to go with my backup report. The discovery of Sedna, the most distant known object in our solar system, has thrown the definition of 'planethood' into confusion..."

After first period let out, Lisa encountered Bart and Milhouse in the hallway. "Hey, Lisa," Milhouse greeted her, "Bart and I have decided we want to be scientists when we grow up."

"That's fantastic," said Lisa with a proud smile.

"Then we can build our own killer robots," Bart enthused.

"And have them fight each other," Milhouse added.

Lisa groaned miserably.

"I'm gonna send my robot into the past to kill Principal Skinner before he becomes principal," said Bart.

"I'm gonna send my robot into the past to kill Principal Skinner before he's even born," said Milhouse.

The boys suddenly heard a familiar throat clearing. Whirling around, they saw Principal Seymour Skinner towering above them.

"Come with me if you want to live," the principal commanded them.

"Uh-oh," said Bart nervously.

----

Still deeply troubled, Lisa trekked to the Buddhist temple a few hours after the end of school. Lenny and Carl were there, clearing their heads after a stressful day at the power plant.

"Hello, Lisa," Carl welcomed her. "You look a little blue."

"I'll refrain from making an obvious yellow joke," added Lenny.

Lisa knelt in a lotus position before the altar, and sighed plaintively.

"I used to think science would solve all our problems," she related. "But now I see that every scientific breakthrough just gives people more efficient ways to kill each other. When will it all end?"

"We've got nuclear weapons, and we haven't blown up the world yet," Carl pointed out. "So maybe there's hope."

"I believe that someday Buddha will come down and turn Earth into a paradise," said Lenny. "But not before the United Nations tries to enslave everybody by tattooing bar codes on their foreheads."

They engaged in meditation, but Lisa found no inner peace. Suddenly Bart appeared in the entrance to the temple, wearing a crash helmet and clutching his skateboard.

"Yo, Lis," he called. "I think you'd better come with me."

Lisa rose to her feet and gaped slightly, surprised that her brother had actually set foot in a Buddhist shrine.

Bart waved at the two power plant employees. "Hi, Lenny. Hi, Carl." He waved at the Buddha statue. "Hi, Lisa's god."

As he led his sister down the street, Bart informed her of what he had heard. "The police thought they'd deactivated the robot, but someone broke into Frink's warehouse and turned it back on. It's loose again."

"You're kidding," Lisa marveled. "That means Professor Frink may not be the murderer."

"Or else he has an accomplice," said Bart.

"I've got to get to the bottom of this," said Lisa with determination. "I've got to clear the professor's name."

"What about me?" Bart wondered. "What can I do?"

"You can shut up and let me think."

Just as they had almost reached the door of their house, Lisa stopped abruptly. Her eyes widened in horror.

"No," she said in a hushed tone. "Please let it not be true."

"What?" Bart asked her.

"I think I know who the culprit is."

----

Has Lisa solved the mystery? Find out in the staggering conclusion!