A/N: I don't own Phineas and Ferb or Harry Potter. Now READ and REVIEW!
The first week of Phineas's deception went surprisingly well. While they found it odd that he wasn't on their attendance sheets, Phineas simply informed them that he was actually a Muggle who built a mechanical wand and had stowed away on the train in his brother's suitcase.
"I'm sorry, Flynn," the reply would almost always be. "I wonder why the Ministry forgot to add you to the list of students?"
His mechanical wand, a thing of utter beauty, performed its tasks well. The only problem was that Phineas had to tell it specifically what to do in a scientific manner, and then set the command equal with a "spell". For this purpose, Phineas had to learn the incantation and then, to program the spell, quickly request a bathroom break.
To get rid of suspicion of his activities, he found himself forced to quaff horrific amounts of pumpkin juice at each meal.
Pumpkin juice was not his favorite hydrating substance.
Phineas and Ferb's classes were well enough. Phineas liked Professor Binns's class, the ghost professor who taught History of Magic, the best, because it was pretty much an extra hour of sleep each day. Ferb seemed fond of Potions and Astronomy, because it required so little talking on his part. They met up with Harry, Ron, and Hermione regularly.
On a fine Friday afternoon, Phineas and Ferb had just finished Arithmancy classes and were going to meet the three Gryffindors in the courtyard. Harry waved them over to a bench.
"I got a letter from Hagrid this morning; he's the keeper of the grounds. We're going to his house for some tea. Want to come?" Harry asked.
"Tea?" Phineas smiled and asked, glancing at his brother. "Man, Ferb, they don't let you forget for a second here that you're in England, do they?"
Hagrid's hut was at the edge of Hogwarts's grounds, near the Forbidden Forest. It was a bit of a walk, but they arrived in due time.
From inside the hut there came loud, fierce barking. "Back, Fang, back!" an equally gruff voice told the dog. Soon, the door was opened and Phineas and Ferb got their first look at Hagrid.
""Arry!" Hagrid exclaimed. "Nice te see yer! Glad you got the letter." He glanced over and happened to see Phineas and Ferb standing there.
"'An what's this? Cartoon characters! 'Arry, ye need to introduce me, here, who's this?"
Phineas and Ferb walked up and shook his massive hands. "Hi," Phineas said. "I'm Phineas, and this is my brother, Ferb! I believe we gave a shower to one of your northern kinsfolk in our Christmas episode title sequence."
Hagrid welcomed them into his hut and introduced him to his dog, Fang. A fire was going in the fireplace, and Hagrid took a tray of something called "rock cakes" out and offered them to his guests.
Phineas took a rock cake. He tapped it with his fingernail and listened to the resonation. "How exactly did you make these, sir?"
"Er..I, um..well...the fire, and some dough...wasn't that old, I thought..."
Ferb had already set up a laboratory analysis station. He placed a rock cake under the microscope and let his stepbrother take a look.
"Wow. It appears that even the individual atoms have been fused together," Phineas noted.
Harry saw something clipped from the newspaper on Hagrid's table. He picked it up and read the text.
"Hagrid!" Harry said. "This story is about a break-in in Gringotts, but the vault they tried to rob – vault 713 – that was the one you took me to!" Harry turned around in his chair. "Hey, Phineas!"
"Is it physically possible for something to be harder than a diamond?" Phineas was asking Ferb, holding up a clear gem with a prominent scratch. "Oh, yeah, Harry?"
"When I went to Gringotts," Harry recounted, showing Phineas and Ferb the newspaper clipping, "we visited this vault. Later, someone tried to rob it."
"What did you take out of it?" Phineas asked, reading the clipping.
Harry shook his head. "I don't know exactly. It was about two inches long, but wrapped up in cloth. What could it have been?"
Ferb shrugged. "A two-inch ruler, perhaps?"
Hagrid coughed loudly, and reached over to take the paper from Phineas. "That's none of yer business, 'Arry and Phineas. Must've been real Dark Magic te break into a Gringotts vault, so let's not get messed up in it, eh?" After that, Hagrid was almost too nice to them. When it was time to say good-bye, he loaded their pockets with rock cakes. Harry, Ron, and Hermione had been too polite to say no, and Ferb had wanted some samples for further laboratory analysis.
All of them were thinking that their visit to Hagrid's hut had given them more to think about than all of their classes combined.