Lucious was a part of the plan,because he had to put the Diary into Ginny's cauldron so he obviously knew what was going to happen, and Dobby probably picked it up, being around the house and all.

didn't lucius plan slipping the diary into some hogwart's student's bag so he could help Voldemort come back as his sixteen year old self?

I totally agree with you! Plus Lucius hated the Weaslys So it would fit...

good point.
i mean DUH Dobby overheard the Malfoys.
but i thought Lucius didnt know Voldemort was back. he didnt believe it.
so he had not contact with the dark lord..so how did he kno something was going to happen?

read the thread about Why did Riddle give Ginny the diary.
lots of people, including me, said Lucius gave Ginny the diary because he needed things that could connect him to the dark lord out of his house and he hated the Weasleys so he just gave it to them.
he might have known it held something..but he didnt kno what.

so how would they kno something was gonna happen?

Well...obviously they (the malfoys) would have disgused it..they would have already talked it all over. So Dobby would have overheard.
He was just warning harry!

Lucius Malfoy was given the diary by Voldemort to keep safe, but when voldemort fell Lucius thought he was gone for good and then he gave the diary to Ginny not knowing all that it could do. When Voldemort came back he was extremly angry with Lucius that the diary was gone seeing as the diary was a Horcrux.

Like you said Dobby lived with the malfoys so he hears things. The plan wasnt to give ginny the diary he did it to early and without orders. he thought that his master was dead remember. He just gave it to Ginny in hopes that something would happen and it did, in a way. The plan was to bring ol' voldy back but she freaked out when things went to far. Dobby couldnt really tell harry what was happening but he let him know that it was his master that put the faulty plan into works. Lucius was brain dead in that area and wasnt doing what he was really told to do. thats just my opinion though

I think Malfoy knew some of the things Voldemort did to prevent himself from dying, and he knew LV was going to come back someday. So he tried to give it a head start by giving Ginny the diary.

Also, I think house elves are much more powerful than wizards give them credit for. They have magic beyond a wizard's capabilities, and those wizards don't even notice it because they believe house elves are beneath them. And, of course, those house elves won't use magic against their masters. But I think Dobby sensed something was going to happen, through magic or a house elf's intuition, and felt compelled to warn Harry.

Dumbledore says it to Harry in HBP, I dont remember the exact words but: "Of course Voldemort told him diary was a key to Chamber of Secrets, but he never told the real value of it. He was so sure of Lucius's loyalty to him that he never thought Lucius might throw the diary away. When Lucius was sure his master was dead, he gave it to Weasley's little daughter, to get rid of it, to bedaub Weasleys and to open the Chamber."

I think they knew because draco says that his dad knew the chamber was opened but he wouldnt tell draco who it was. so they knew it was t.m.r. Lucius knew what it would do but he didnt know it was a horcrux

Yes, of course they did. Lucius gave Ginny the book, so of course they would know that something was going to happen that year at Hogwarts.

Obviously, the Malfoys knew. I mean, Lucius did slip the diary into Ginny's cauldron, so they had to have known something. And I believe House Elves are actually very powerful. Dobby could have found out from overhearing them or other Death Eaters.

I think that like Kreacher, Dobby some how found out. Volemort may have said that if in fact something was to happen to him, all Lucis had to do was simply give the diary to a Hogwarts student. Maybe Voldemort thought Lucis would give it to Draco. Than he simply would of stated that the diary will do the rest. Than Dobby might have over heard Voldemorts real name from a few older death eaters and information about what happened to while Voldemort and those Death Eaters were in school. Than Dobby may have put 2 and 2 together. The older death eaters would of known more than a newbie death eater. Hermoine/Dumbledore said that wizards dont give lesser creatures the credit they desreve. Plus the death eaters wouldnt of thought a house elf was smart enough to figure it out. I dont think Lucis would of gotten rid of the diary knowing what it would really do. There was an inquiry going on, so the fastest way to get rid of the diary without tracing it back to him would of been the best method. Its a crazy theory, but its not impossible. Anyway, just a theory.

Not to mention he may have figured out about the diarys true potental after the chamber opened. Voldemort spoke parseltounge. He may have finally placed that with the chamber of secrets. He may have figured out the diarys real purpose after he tired to rid himself of it.

Wasn't it Voldemort himself who demanded Lucius to give the book to Ginny? Though Voldemort was angry with Lucius later because he treated the horcrux neglectfully? He never really told Lucius it was a horcrux, but probably that it was an important thing, and so Dobby got to know at the dinner table or something.

Well it is a good point. I don't think Dobby knew specifics because Lucius did not know their was a part of Voldemort's soul inside the diary. He probably knew that something to do with Voldemort was going to attack Hogwarts and Dobby worked out the rest for himself being the awseome house elf that he is.

Probably, I think that's why Dobby was warning Harry not to go to Hogwarts and obviously Dobby lives with the malfoy's and draco's dad is a deatheater so he probably knew Voldemorts plans and Dobby was earwigging when lucius was talking narcissa I think.

He might have overheared lucius and narcissia gossiping about it.

The Malfoys knew.

totaly agree with u

Yes. He probably heard every little detail about it from the malfoys. And they didn't expect him to go and tell Harry so they didn't think anything of it.

Wow, never really thought about that! I wasn't actually ever sure as in the book Draco tells Crabbe and Goyle he has no idea who opened the Chamber of Secrets... However, Dobby could of overheard Lucius and Narcissa talking about it.