It was a terrible day for Harry Potter. First, he got lost in some side street to Diagon Alley, only for Hagrid to rescue him ignominiously. Now he was being forced to pose for a picture for The Daily Prophet along with this overly smiling smarmy new Defence Against Dark Arts professor, Gilderoy Lockhart. Just being near the Wizard set his teeth on edge — there was something that made him feel unsafe in the Wizard's presence.
It was then that something strange happened, during the camera's brief bright flash. Something powerful seemed to be coming at him. Harry, with a decade of dodging his cousin Dudley's blind-side attacks, lunged to the right. As his future Professor was holding him tightly around the shoulders, this dragged the buffoon into the incoming thing's path.
It happened then, before the camera flash vanished, something hit Gilderoy Lockhart. He swayed a moment in the aftermath, then his eyes rolled up and he slipped to the floor, unconscious, taking poor Harry with him.
There was utter chaos in the crowd when their favourite author and five-time winner of Witch Weekly's Most-Charming-Smile Award collapsed over the Boy-Who-Lived. Molly Weasley immediately dragged young Harry Potter from beneath the unconscious Gilderoy Lockhart and looked in horror at her favourite author on floor.
The management of Flourish and Blotts immediately responded to the crisis and transferred the stricken Wizard to Saint Mungos. They promised his disappointed fans that there would be another autograph signing at a future date.
It took half an hour to disperse the crowd remaining at Flourish and Blotts, most of them going to Saint Mungos where the expert healers were trying to awaken Lockhart.
During that time, Draco Malfoy announced Harry had caused this by striking the preeminent author with a Dark spell. That developed into a fight between the Weasleys and the Malfoys. It ended when the half-giant Hagrid separated the two adult combatants, but not before Arthur Weasley punched Lucius Malfoy in the nose. No one noticed, in that commotion, the extra book slipped into the cauldron of a young Miss Weasley, the seventh child of the Weasley family and the first witch in seven generations.
Gilderoy Lockhart, Order of Merlin, Third Class, Honorary Member of the Dark Force Defence League, five-time winner of Witch Weekly's Most-Charming-Smile Award, and soon to be Hogwarts' most beloved Defence Against the Dark Arts Professor (at least in his own mind) returned to consciousness feeling lightheaded and extremely tired. The Healers informed the gathering crowd eagerly awaiting news regarding their favourite author that it was merely a case of exhaustion and with good nutrition potions, he would be fine soon. What startled everybody was hearing, "WHAT THE BLOODY HELL IS THIS?" from the room housing the self-important popinjay.
For some reason the photograph taken at the bookstore came out blank.
...
It didn't take long for Harry to realize Death had played a prank on him. But while most people would have been mad, he was grinning happily. Sure, Death may have thought Harry would be humiliated in being bound to the body of a bloody fraud and cheat, but it didn't understand that Harry would not mind being a mistreated house elf or even Fang, Hagrid's giant dog. As long as he could prevent the widespread destruction caused by the war, he was happy. And being Lockhart gave him a front-row seat on the events of Second Year.
Getting out of St. Mungos was a bit trying, as he seemed to be at war with himself. Finally, he just relaxed and let things flow instead of trying to fight. He still remembered how to get to back to Gilderoy's home, thankfully. And he was equally happy that he didn't splinch himself in his current muddled state.
He had a lot of work to do in the short amount of time before school started.
First on his agenda was adjusting to his new body. Fortunately, after years of battle, he knew how to adapt quickly to any new situation and use it to his advantage. He swiftly realized that he was neither Harry Potter nor Gilderoy Lockhart, but a confusing combination of the two. At any given moment, one or the other seemed to be in command. Thus, sometimes he acted just like he remembered Lockhart acting like in Hogwarts — as a smarmy publicity hound braggart, basking in the firm belief that he was adored by everyone and that his every pronouncement was met with acclaim. Other times, he was humble Harry wanting to avoid the crowds, downplaying his achievements, and just craving to pass unnoticed in the background. In other words, one wanted to be a Star, the other wanted to be Normal.
Fortunately, melding with the narcissistic Wizard had one tremendous side-effect, his Post-Trauma Stress Disorder was almost gone. The sudden panic attacks were moderated by Gilderoy's sunny confident personality. No more paralyzing bouts of certainty that Voldewhore was stalking him, because Lockhart loved the fans constantly following him. No more flashbacks where he attacked anyone around him thinking they were Death Eaters — one of the reasons he had been hiding alone in the radiation scarred ruins was to protect those around him. Instead, the smarmy buffoon acted as a buffer — he simply couldn't conceive why anyone would want to attack him. Gilderoy's wand would still drop into his hand at any startlement, tip glowing with an uncast spell, but he quickly returned it to its holster and no one ever noticed.
As the days passed, however, he began to notice that more and more, the Harry Potter he remembered was becoming Lockhart. And that Lockhart was becoming Harry Potter. The line between the two began to blur and disappear. He had Harry Potter 's courage and moral fibre for wanting to do what was right and Gilderoy Lockhart's cunning and smooth talking confident ways. He still craved the attention and admiration of others, but at the same time demanded that it be for the right reasons. He wanted to dress and look the part of a successful public celebrity, yet at the same time to be nondescript and unnoticeable. He wanted to be the focus of everyone's attention and to hide in the shadows, unnoticed.
His emotions were in a constant turmoil between his two characters. That required a good week or two to settle down. He still vacillated between the two states, but now the ends were not so far apart.
Gradually, the smouldering pain of inner turmoil as the two personalities merged subsided. Harry/Gilderoy Lockhart was a brand new person, with Harry's determination, speed, and empathy, and with Gilderoy presence, quick cunning, and confidence. They still quarreled in his head, but now it was over nuances of their amalgamated personality.
The most surprising discovery was that Harry enjoyed flirting with the Witches just as much as Gilderoy — it was actually fun! And Gilderoy's confident manner easily dragged the hesitant, insecure Harry into conversations loaded with innuendo whenever the Witches were around.
He noticed his power levels increasing too. In a scale of magical power calibration, from what he had seen or experienced, he would give Dumbledore a ten, Voldewhore an eleven, and himself a seven.
Gilderoy may have been a fraud, but he was very good at extraordinarily difficult Memory Charms. Harry gave him a rating of three on the same scale. Of course, he had never had the opportunity to measure any of these on an objective scale, so he could have been wrong in his relative rankings.