Chronologically, this story would take place a few years before the show started.  Monica's like 25, Chandler and Ross (still married to Carol) are 26ish.  Phoebe's there, she lives with Monica, and Joey and Rachel aren't introduced yet.  I think that's all you need to know.

Disclaimer:  I don't own anything.

                "I need to tell you guys something," Monica started nervously.  She looked at the four people whose attention she'd just caught.  Her big brother, protective, caring Ross and his wife Carol.  Her roommate, flaky, loyal Phoebe.   And Chandler, who was always there for her, her best friend.

            "You gonna tell us or do we have to guess?" Chandler quipped after a few awkward moments.

            "Shut up.  This is kinda serious.  I didn't tell you, because I didn't think I'd get it, and didn't want to make a big deal out of it, but… a few months ago I applied for a job in Boston."

            "Boston… Boston's in Massachusetts," Phoebe said, confused.

            "Yeah.  Well, it was right after I broke up with Bryan… I was upset, and depressed… I just wanted to apply, I told myself I'd deal with that part if I was hired."  She surveyed their expressions.  Phoebe's was still intently listening.  Ross's had fallen a little, expecting the next words out of her mouth.  Carol's was warm and understanding.  And Chandler's- Chandler's she could barely look at.  His mouth was set in a hard, firm line.  His warm blue eyes had gone cold.  His right knee was jerking around nervously.

            "I got it," she said quietly. 

            "I guess I don't have to ask whether or not you're taking it, if you're telling us about it," Ross said, a little sadly.

            "I just… I think it would be a great opportunity.  I was offered the head chef position.  It's a really well established restaurant…" she trailed off.

            "You're leaving?" Phoebe asked incredulously.

            "I think so."

            "Don't say you think so, if you know it.  Don't bullshit Monica," Chandler said harshly, finally speaking.

            "Chandler," Carol admonished. 

            "Sorry," he muttered, closing his eyes briefly.

            "I know it's.. I know it's a lot of information, a lot to take in," Monica said quietly.  "I just thought you should know that this is what I want right now."

            "When do you leave?" Phoebe asked sadly.

            "Three weeks from tomorrow."

            "THREE WEEKS?  Have you even told mom and dad yet?" Ross asked incredulously.

            "No, not yet."

            "Well, were you planning on it?" Ross asked annoyed.

            "Of course I was planning on it, Ross.  Look, I know you guys are probably going to be mad at me, but I really think that this is the best thing for me right now, and I hope that you can understand that."

            "Congratulations, Monica," Carol offered after a slight pause.

            "Thanks," she said, surveying her friends once again.  Phoebe jumped up and grabbed her tightly.

            "I'm going to miss you," she said, holding back tears.  Monica hugged her back fiercely.  "I'll miss you too Phoebs, so much."  They pulled apart and wiped their eyes.  Phoebe stroked Monica's hair affectionately.  "If this is what you really want-"

            "It is," Monica answered.

            "Then I'm happy for you," Phoebe finished.

            "Me too," Ross said quietly.  Monica turned to face him.

            "Really?" she asked.

            "Really.  I only want the best for you Mon.  It'll suck, you leaving.  But it's your life.  I love you," he said, giving her a hug. 

            All eyes fell to Chandler.  He got up awkwardly.  "I have to go."

            "What?" Monica asked.

            "I have to- I just have to go," he said quickly, before practically bolting out the door.

            "He's just-" Ross began.

            "I have to go find him," Monica said, cutting her brother off and following Chandler.

            She found him in his apartment, opening a beer and collapsing on the barca lounger.

            "What the hell was that?" she asked angrily.  Her blue eyes were dark and flashing. 

            "I'm sorry, do you seriously think you have the right to be mad at me?" Chandler asked her incredulously.

            "Yeah, that's exactly what I think.  I just had to tell you guys a really hard thing, Chandler, and I at least expected you to understand."

            "You expected- Jesus, Monica, how can I understand this?  How can I understand you?"

            "Because you're my best friend!  Because you should be wanting the best for me, wanting me to do what I have to do.  And at the end of the day, even if you still don't think I should go, you should be faking it, okay?  Because I can't do this without you," she said, her words softening at the end.

            "Yeah, well, maybe I'm just a terrible friend," he muttered.

            "You're not.  You're just being a jerk right now," she said, tears pricking at her eyes.

            He saw that she was on the verge of tears and sighed.

            "Yes, Mon, I am.  I'm completely selfish.  I don't want you to go because I'd miss you too much, and I'm being a horrible friend."

            "You're not realizing that I'm going to miss you too, Chandler.  I don't know what I'm going to do without you across the hall, to complain to or watch bad movies with at two o' clock in the morning, or ditch work with to play Frisbee in the park, or order Chinese with and only eat half and then trade…"  He got up and walked toward her. 

            "Monica… is this what you really want, or is this a knee jerk decision because of what happened with Bryan?" he asked her, looking into her eyes.

            "Honestly?  It's a lot of things, and that does play a part in my wanting to leave.  That was the initial reason.  But the more I think about it, the more I feel… stifled, or something.  Like, I can't stay in New York without sacrificing part of myself.  And if I stay here with you guys, my security blankets, my safety net… then I'm never going to experience anything, I'll never find out who I really am."

            "I'm not going to lie.  I don't want you to go.  But if you need someone to hold your hand on the way to the airport… you know that person is me."

            Monica threw her arms around his neck in one fluid movement.  He wrapped his arms around her tightly, breathing in the scent of her shampoo, feeling her shoulders shake slightly and knowing she was crying.  She held him closer to her.

            "I love you, Chandler.  Thank you," she said, trying to stop her tears.  He closed his eyes and tried to fight his own.

            "I love you too, Mon."

"Oh your reputation's so golden,  You're never lonely and you're never home
I know you've been talking about leaving,  You've lost all your feeling for this town
Paint your nails and put on your lipstick,  You don't want to miss your ticket out
Just because you graduate from school, so high in the gene pool, that's your point of view
but when you're broken down, and no one else is around
you'll come running back to this town… and I'll be there, yeah I'll be there

'cause I remember how we drank time together
and how you used to say that the stars are forever
and daydreamed about how to make your life better
by leaving town, leaving town…"

-Leaving Town, Dexter Freebish