it's a long story 

A way of saying "I don't want to tell you"

From 'The Fast and The Furious'

'so how d'you know him?'
'It's a long story'
'We've got a 40 mile hike.'
'A business deal went sour,And once I made the mistake of sleeping with his sister'.

it's a long story by Jay & Silent Bob June 24, 2004

It's a Long Story 

Something said by some one when they don't actually want to tell you what happened.

Person #1 - So where were you yesterday?!

Person #2 - It's a Long Story...

It's a Long Story by me218 September 25, 2008

it's a long story 

Said when they ask you something you don't have time to explain

Hey, aren't you at school?

Not today. It's a long story.

it's a long story by Simon The Great And Howling One January 14, 2008

its a long story 

a phrase when a person does not want to go into a certain subject; or speak of a certain matter.

Person 1:Hey I heard you in Jenny broke up what happened man.
Person 2: Yea its a long story.(thinks in his head:I'm getting tired of everyone asking that I don't want to talk about it what don't they get?

its a long story by Mrusername798 April 16, 2010