So, Lucius Malfoy concocted a plan in Harry Potter that he hoped would get Arthur out of his way. He happened to have a diary that, though he didn't fully understand, would result in the opening of the Chamber of Secrets.
Malfoy still possessed the diary and, in 1992, he planted it on Ginny Weasley, hoping to kill three birds with one stone by sabotaging Ginny's father, purge the school of Muggle-borns, and eliminate an incriminating Dark artefact.
Some time during the First Wizarding War, Lord Voldemort entrusted the diary to the Death Eater Lucius Malfoy. The plan was to use the diary to reopen the Chamber, but Voldemort fell before this plan came to fruition.
Why did Lucius Malfoy put the diary to Ginny on Reddit?
Lucius Malfoy slipped Ginny Weasley the diary in Diagon Alley, and we know the reason he did so was to a) harm as many Mudbloods as possible, and b) to harm the Weasley family and their reputation.
Cookie Gives To Lucious Divorce Papers | Season 6 Ep. 9 | EMPIRE
Did Lucius put the diary in Ginny's cauldron?
We first meet Lucius in Flourish and Blotts, where he insults Harry and the Weasleys. He picks up a tattered book from Ginny's cauldron, only to secretly slip the diary into the cauldron when he returns said book.
Lucius knows the diary is cleverly enchanted, but is not aware that it is a horcrux containing a part of Voldemort's soul. He is careless with it and punished by Voldemort himself.
Most of the people thought the chamber of secrets was a myth. Voldemort had given his diary to Lucius and asked him to take care of it. Lucius thought it was something important but didn't know it was an horcrux or that it would unleash a monster.. He merely did it because Arthur Weasley was conducting raids.
I find it most likely that Tom thought Ginny's soul was perfect because she was so young and innocent and had lead a very sheltered life, always protected by her family. This made her both very willing to trust Tom and very unwilling to believe that he was using her to attack her fellow students.
How did Harry know to stab the diary with the Fang?
In the book, it says that Harry looked at the diary and the fang he happened to have in his hand, and just suddenly knew to stab it, “As if it is what he had come here to do.” It was entirely intuitive.
Dumbledore told Harry in Half-Blood Prince that Tom Riddle's diary had been his first clue that Voldemort had created a Horcrux and that there was likely more than one.
Lucius Malfoy's failure at the Department of Mysteries combined with accidentally destroying part of Voldemort's soul with the diary of Tom Riddle resulted in his loss of any standing with the Dark Lord. Some believed that he was safer in Azkaban than being free. Lucius was sentenced to life imprisonment in Azkaban.
After being healed, Harry took the fang and stabbed Riddle's diary, destroying that Horcrux beyond magical repair. Because Harry had stabbed the Basilisk with the sword, it was imbued with Basilisk venom, and was therefore able to destroy Horcruxes as well.
It is true that towards the end of the second book and movie, Harry Potter and the Chamber of Secrets, Dumbledore insinuates that he knows Lucius planted the diary on Ginny, but he never says it.
Because he and his family defected from the Death Eaters they were pardoned for their crimes after Voldemort's final defeat and did not serve a stint in Azkaban. He and Narcissa later had a grandson, Scorpius Malfoy, after Draco married Astoria Greengrass.
Harry Potter, Ron Weasley, and Gilderoy Lockhart came to the rescue. Ron and Lockhart were stuck behind an avalanche of stone, so the battle was fought mostly by Harry. Harry managed to defeat both the Basilisk and the memory of Tom Riddle, thus saving Ginny's life.
Unbenownst to her the diary was in fact cursed, and by writing in it she was feeding the spirit of a young Lord Voldemort who had used the diary as his first Horcrux. As she succumbed to the dark magic Ginny was forced to re-open the Chamber of Secrets and release one of Hogwarts' darkest secrets.
J.K. Rowling once explained that Ginny Weasley is so powerful because she is the seventh child of a seventh child. This is part of folklore that has been around for a long time.
“'By planting the diary on Arthur Weasley's daughter, he hoped to discredit Arthur and get rid of a highly incriminating magical object in one stroke. '” Did Lucius Malfoy realize Tom Riddle's Diary had a magic quality before he gave it to Ginny Weasley, even if he did not know it was a Horcrux?
He knew. Lucius was arrested at the end of the first war with Voldemort but convinced the authorities that he'd been Imperiused. It's possible that any evidence that would have proven otherwise was provided by Snape, whose cover Dumbledore couldn't risk.
In fact, he was in Lord Voldemort's closest circle as a Death Eater. He despised Muggles, Muggle-borns, those he saw as blood traitors and tried to instil those values in his family. Those beliefs certainly fed his ego, as he thought himself to be superior to those who did not share his background.
Rowling commented that "The moment Draco got what he thought he wanted, to become a Death Eater, and given a mission by Lord Voldemort, as he did in Harry Potter and the Half-Blood Prince, reality finally hit him" because his dream was "so very different".
During the Battle of the Seven Potters, Harry Potter's wand shot a stream of golden flames at Lord Voldemort of its own accord. The spell was powerful enough to break Lucius Malfoy's wand.
Someone as shrewd and cunning as Lucius' character, who made sure to get rid of Dark magic items earlier wouldn't have intended to use it on Harry. Isaacs, however, improvised and chose to ad-lib the beginning "Avada..." of the Killing Curse before Dobby attacked him.
