Thirteen year old Teddy Lupin stepped through the barrier at Platform Nine and Three-Quarters.  He looked around.  Steam obscured most of the platform, as usual.

Harry helped him put his trunk and owl onto the train, then beckoned him over to a corner of the station.

"Come over here for a minute.  I need to talk to you."

Curious, Teddy followed him over.

"Now that you're thirteen, I think it's time for you to have this."

Harry held out a piece of parchment.  It was entirely blank.

"A spare bit of parchment?"

Harry chuckled.  "That's what I said when Fred and George Weasley first handed me this.  They had no idea who made it, of course.  This was made by the Marauders."

Teddy looked up, shocked.  "My- my dad?  And yours?"

Harry nodded.  "And my godfather, Sirius Black, and-" his expression darkened slightly, "-the man who betrayed my parents, Peter Pettigrew."

Teddy frowned, a question occuring to him.  "Why were they friends with him?"

"I can't fully explain it myself, but he was their friend, a genuine friend, at Hogwarts," Harry explained.  "They made this during their time at school."

He glanced at the clock.  There was one minute to the train leaving.

"You'd better go.  Find a good use for that, and please don't do anything illegal."

Teddy frowned as Harry pushed him towards the train.  "But you haven't told me how to use it!"

"Ah, yes, that."  Harry frowned a moment.  "You've got to solemnly swear what you're up to, and it can't be good.  And when you've managed your mischief, make sure you wipe it."

Teddy gaped as Harry pushed him onto the train just before the doors closed.  "But that doesn't tell me anything!"

Harry winked.  "Trust me.  And if you tell them who you are, I'm sure they'll give you some hints if you ask the right questions."

Teddy's mouth was still open as the train started to move.  "What?"

"Trust me.  And have fun!"

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"Hey, James!"

"Yeah?"  James looked up.

"Come here.  I need to show you something."

James followed Teddy over to the garden.  "What is it?"

Teddy looked around, making sure no one was watching, and pulled out an old piece of parchment.  "It's time you got this."

James looked at the parchment, then back at Teddy.  "A spare bit of parchment?"

"Not just any old bit of parchment."  Teddy took out his wand and tapped the map.  "I, Teddy Lupin, would like to introduce Messers Moony, Wormtail, Padfoot, and Prongs, to James Sirius Potter, son of Harry Potter."

Writing began to appear on the map as if written by an invisible hand.

Mr. Moony is honored to make your acquaintance, Mr. Potter, and would like to say farewell to Mr. Lupin, and best wishes for the future.

Mr. Wormtail would shake your hand if he had one, Mr. Potter, and hopes he can be of assistance in the future.

Mr. Padfoot is delighted that the map is being passed on again, and is curious if he heard Mr. Potter's middle name correctly.

Mr. Prongs is astonished to hear the name of Mr. Potter, and inquires how this came to be.

James looked at Teddy curiously.  Teddy tapped the parchment again.  "Yes, his name is James Sirius, and he needs some hints about what this is.  I'll leave you with him now.  Farewell, and Mischief Managed."

Farewell, Mr. Lupin.

Farewell.

Goodbye, Mr. Lupin.

Mischief Managed.

Teddy looked up at James, and James was astonished to see tears welling up in his eyes.  "When you get to Hogwarts, ask a few questions.  They'll help you out.  They did for me."

James nodded solemnly, taking the parchment carefully.  He thought he had never felt more honored to recieve something in his life.

"Oh, and James?"

James nodded again.

"Please don't do anything illegal.  Your father will kill me if you do, and I'd never forgive myself if you got caught."

James nodded for the third and final time.  "I'll be careful, Teddy.  I promise."

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Sixteen year old James looked down at the map.  "Mischief Managed."

He found Albus out on the grounds after Quidditch practice.  "Hey, Albus, can I talk to you?"

Albus nodded, waving his friends on ahead of him.  "What's up?"

James held out the map.  "I think it's time for you to have this."

Albus took one look at the map and started laughing.  James looked hurt until Albus stifled his laughter and explained, "James, you've always lent me the map when I needed it.  We've been practically trading off for two years now.  I don't see why one of us has to have it for themselves.  We're brothers, we should share this.  Now that Lily's a third year, though, I suppose we'll have to share with her, too, like Teddy did for you and you did for me."

James looked taken aback.  "Really?"

Albus nodded.  "Really."

James smiled, looking touched.  "Thanks, Albus."

Albus pulled his older brother into a hug.  "Come on.  It's nearly time for dinner."

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Lily sat on one of the old pots in the greenhouses, utterly confused.  "What are we doing here?"

Albus and James looked at each other, grinning.  "Now that you're thirteen, just as Teddy did for me, and I did for Albus, it's time to introduce you to the Marauder's Map."

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A/N:  Hope you enjoyed!  I had a lot of fun writing this one - tell me what you think!