John Titor from the year 2036 has return to the year 1991 in June to warn Albus Dumbledore that the Dark Lord will return fully powerful in four years from now. John showed Albus a 2007 satellite picture of Hogwarts completely flattened. Albus looked at the picture and sure enough, there was the black lake and the distinct towers, except the trees were all missing. Albus looked up to John and said, "It not possible! The Dark Lord could never attack Hogwarts!"
John said, "I am afraid they did. You will be murdered the year before by someone you trust. Also most of the good side is killed as well and this school will be destroyed. I have the proof." He took out seven books on Harry Potter, showed Albus, and said, "In the fourth year this school will be hosting The Tri-Wizard Tournament.
Albus stood up and said, "That is a well kept secret and I don't know how you found out this out!" John handed the Harry Potter and the Goblet of Fire book and turns to the proper page. He shows Albus. Albus read that part of the book. He looks up and gives John a bad looks. Albus looks at the publish date and saw that it was publish in 2000.
Albus looks up and said, "This book is from the future and it is a Muggle book. They are not to know anything about our world." John said, "After the destruction of your world, the person gave information to the author to be published as a memorial to Harry Potter. I am warning you, you need to remove Cornelius Fudge from office soon. He will make a huge mistake that will result in the destruction of Hogwarts." Albus couldn't take anymore of this and asked John to leave.
John went to his time machine and disappeared from sight. Albus decided to take this interview and put it into his pansieve. He forgotten about this interview and nothing was changed.
John fails again at another time travel adventure.