Together, they assembled a small team of thieves and murderers, training them for the death-defying siege of Hogwarts castle. In reality, Lucius had no intention of accompanying the siege. He planned to use the distraction created by the siege to sneak alone into the Forbidden Forest and seek out the hidden dagger. Despite his and Gregor's training, in fact, Lucius fully expected the siege team to be captured and sent to Azkaban. Frankly, so long as they provided the short distraction Lucius needed, he didn't care. They would be one small sacrifice in the ongoing work of the fallen Dark Lord.
The siege never happened though. Less than a week before the planned trip to Hogwarts castle, Lucius was alone in the manor house on Cannery Row when one of the thieves he'd hired for the siege team, a young man named Malcolm Baddock, stepped out of the shadows, a knife glittering in his hand. The man grinned, ordering Lucius to turn over the gold hidden somewhere in the house.
"Give it to me and maybe I'll only cut out your tongue, old man," Baddock had said.
Lucius had merely sighed. He closed the book he'd been reading and, almost lazily, produced his wand. He fingered it idly, not really pointing it at Baddock. "And what makes you believe, young man, that you won't be killed where you stand by this very wand?"
Baddock's grin widened eagerly. "Because this here's my lucky knife, it is," he said, displaying the darkly glinting blade. "It's not failed me yet. It'll kill you three times before you hit the floor, you daft old coot. No wand's ever been any good against it before, and yours won't be any different. Now take me to the gold!"
Lucius narrowed his eyes. "Tell me, my friend," he said silkily, "does your lucky knife know when a wizard is going to do this?"
In one deft movement, Lucius drew a short flick in the air. A thin red line slashed across Baddock's throat and he flinched. Blood began to bead from the cut. It dribbled down his throat and Baddock tried to look down at it, frowning rather comically. His face contorted with rage and he reared, hoisting the knife by its tip. As he opened his mouth to speak, however, his head quietly toppled backwards off his shoulders, separating neatly along the line of blood. It fell to the floor with a thunk.
Lucius was already pocketing his wand and wondering if he'd tell the rest of the team what had happened to Baddock when something poked him in the stomach. He looked down curiously and noticed the hilt of Baddock's knife protruding from his robe. A moment later, he heard the thump of the man's headless body striking the floor, dead. Truly, it had been a lucky knife if Baddock had succeeded in finishing the throw he'd begun while his head was still marginally attached.
Lucius reached for the knife to extract it from his stomach. It would hurt, but it wouldn't be fatal, not to a wizard like Lucius. He stopped, however, before his fingers touched the hilt. His eyes widened slowly as he stared at it. The bit of hilt he could see protruding from the slowly darkening folds of his robes was quite ugly and jewel-encrusted. Lucius recognized it. Slowly, he wrapped his fingers around the silver hilt and pulled the blade out of his gut. He barely felt it. He slid to his knees, holding the dagger up, turning it, and watching the firelight play on its dark, bloody blade. He began to laugh.
"Thank you, my Lord," he cried through his laughter. "Even dead, your word rings true! Your final Horcrux has found me! Thank you! I will not fail you! Your final task will be completed!"
Lucius laughed until he was hoarse, only remembering to heal the wound in his stomach when he noticed the blood soaking the front of his robes and pattering to the floor.
It had been over two years since the Battle of Hogwarts, since the inconceivable death of the Dark Lord, but Lucius was finally able to complete his duty. He told Gregor of the surprising appearance of the dagger, and they dismissed the rest of the siege team with a small pay-off in gold, warning them that if they told anyone what they knew, they would experience the same fate as had befallen their mate, Baddock.
Lucius had long since determined the family that would play host to the Dark Lord's 'gift'. They were pureblood, but lowly and poor. Lucius spied on them and discovered that a young woman in the family had just become pregnant. Her name was Lianna Agnellis and her husband had recently been apprehended by the Ministry, suspected of low-level involvement with Death Eaters in the last days of Voldemort's reign of terror. Lucius had vaguely known the man, whose name was Wilfred. He had indeed been a tool of the Death Eaters, although he himself barely knew it. The young man had been extremely simple and gullible, and Lucius himself had even used him as a messenger. It was Lucius who had anonymously informed the Ministry of Wilfred's Death Eater connections, knowing full well that the pathetic man would never be able to implicate anyone by name; Lucius and his cohorts had been far too careful for that. Wilfred was interrogated by the Wizengamot and eventually imprisoned in Azkaban until such time as he might choose to divulge the names of his purported accomplices.
After Wilfred's imprisonment, Lucius paid a visit to the young, quite pregnant Lianna in her tiny flat. He ingratiated himself to her, claiming to be a concerned friend and former associate of her incarcerated husband. Lianna made tea for the two of them and they sat at her rickety kitchen table. Lucius explained that he had both the money and the influence to see to her husband's release if she was willing to perform a small service on behalf of her husband's benefactors. Lianna was desperate: she fell upon Lucius, sobbing and promising she'd do anything to get her Wilfred back home. She asked what Lucius required of her, and he balked, suggesting that she might think twice once he told her. He asked her to take a moment to consider it while she refilled his tea.
As she returned to the stove, sniffing and wiping her eyes, Lucius peered into Lianna's empty teacup, examining the shreds of tea leaves scattered in the bottom. He had to be sure that the child in the woman's womb was a boy child; surely, Lucius was wizard enough to ascertain something as simple as that. He looked closely, squinting, but for some reason, the tea leaves blurred before his eyes. He blinked, trying to focus, to concentrate. In his robes, the Horcrux dagger seemed to vibrate. He felt it reaching into his mind, calling him. It was distracting him. Lately, Lucius never went anywhere without the dagger, but now he suddenly wished he'd left it at the manor house. And then, just as Lianna was returning, settling Lucius' own cup onto the table, the strew of sodden leaves became clear. Lucius stared at them, even reaching for the woman's cup and tilting it to the light. Yes, there it was. There was no question: the child in the woman's belly was a boy child. The leaves proved it. Lucius sighed and smiled with relief. The dagger in his robes went still again.