In 500... (or less)

Hard-headed

The plan had been set in motion years ago. The old man had to be eliminated.

"You think you can handle it?" Sudoplatov asked. "She's rather...uhh...homely."

"I can get close to Sylvia," Mornard said. "She's young and naive. The perfect way in."

Other means had been less effective. Storming the old man's compound with a group of assassins failed in a hail of machine gun fire. Taking him out had proven to be quite hard.

"It's settled then, 'Jacques'," Sudoplatov said, chuckling as he said Mornard's cover name. "You cozy up to the girl, and strike when the moment is right."

Lesser men might have given up. For two long years he lived under the guise of being in love with the young American girl, following her to America when his target had gone elsewhere. He knew he'd get his chance someday, and finally convinced his fiance to move to Mexico City, near the old man.

"Play the long game," Mornard would tell himself as he slowly ingratiated himself to the old man. Each counterfeit kiss, each fraudulent caress would draw him closer to achieving his goal. 

This August day was like any other. Hot and humid. Mornard was now a regular at the old man's fortress, getting inside was no longer a problem. But the moment had not come until now.

"Would you mind reading this for me?" Mornard asked the old scholar. "I value your opinion above all others."

They walked into the study, where the old man sat the paper on his desk, Mornard looking over his shoulder. He let him read for a few minutes, occasionally touching his weapon in his pocket. It had to be just right.

In a flash, Mornard reached into his pocket, pulling out an ice axe. He swung as hard as he could at the old man's head. The feeling of his skull shattering was horrifying, but he was certain he'd finally finished the task he'd set out to accomplish more than two years before.

Except he hadn't.

The old man leapt up from the chair and came after his attacker.

"You sure are hard to kill!" Mornard shouted. "But I intend to rid the world of you once and for all."

The old man screamed as he assaulted his attacker, grabbing Mornard's arm and twisting it with such force that not only did he drop the weapon, Mornard's arm was broken. He screamed in agony.

The commotion was enough to cause the old man's guard to storm the study, where they proceeded to pummel Mornard mercilessly.

"Leave him be," the old man said, stopping the attack. He wanted to hear why Mornard had betrayed him.

"It wasn't easy," Mornard explained. "Years of hunting and stalking you, waiting for the moment. And when it came, you've got such a hard head I didn't even manage to kill you."

"Betraying my trust is the worst wound you could inflict on me," the old man replied. "But tell Comrade Stalin that you've managed to rid him of Leon Trotsky."