Harry Potter and the Clone Wars
Anakin, Ahsoka (14), R2, Rex, and some troopers flee from a Separatist ambush in the Twilight. But because of damage and poorly input hyperspace coordinates, they wind up flying into the Unknown Regions and crash upon a planet with highly ancient technology. The Jedi sense many thousands of Force-users and another very odd but highly potent energy emitting from the planet. Venturing into one of the cities, they eventually stumble upon one of the people who has both Force powers and the strange energy signature. He calls himself Harry Potter (13) and asks them some very strange questions.
Harry quickly decides to help them in any way he can at repairing their crashed ship, in exchange for lessons in how to use their 'Force'. He and Ahsoka become fast and easy friends. The Ministry of Magic quickly confronts the Jedi and freaks out, thinking Ahsoka and R2 are Dark Creatures (racism), trying to arrest and execute them, failing spectacularly. The Jedi rush to repair the Twilight so they can escape this racist, backwater planet before the natives can form mobs and try to crucify them.
After several weeks of converting and adapting the native technology, the Twilight is finally repaired enough for a lightspeed jump. They lift off and jump back to the galaxy proper as quickly as possible, not realizing until later that Harry had stowed away aboard. He wanted to learn more about the Force, Jedi, technology, and the galaxy at large, and he figured that the Jedi would be able to return him home at a later date. Harry's disappearance caused a massive stir in England.
Despite being a stowaway, the Jedi decide to allow him to accompany them. Not only was he rather friendly and open-minded, but he was exceptionally strong in the Force (15,000 medicholarian) and with the Jedi being gradually hunted and worn down from the war, they could use every bit of help available. Returning to Coruscant and reporting what had occurred, the Council decides to appoint Anakin and Ahsoka as Harry's legal guardians and instructors.
When he learns of what a Holocron was, Harry looks up its plans and blueprints and tries to build his own. With some help from Ahsoka and Anakin, he succeeds. He uses it to download information on almost everything in the galaxy: technology, starships, foods, medicines, and especially the Jedi teachings. He even builds his own lightsaber.
Harry is soon sent to the frontlines of battle with Ahsoka and Anakin, watching and learning through doing. His natural affinity for combat allows him to quickly catch up to Ahsoka in terms of fighting skills and basic Force uses.
Meanwhile, when Palpatine learns of a planet in the Unknown Regions that possesses an unnaturally large community of untrained Force-users, he grows hungry to find this planet and take those Force-users, training them to be his own army of private Force-sensitive assassins.