This has been driving me nuts! If any of this sounds familiure PLEASE let me know! :) Ships are: Kag/Inu & Mir/San.
I can't remember the beginning, or much of the middle. I know that it was a long fic. I think Kohaku dies and the gang take his body back to the Slayer's Village for burial. Naraku has either just been defeated, or they defeat him along the way.
But what I do remember is this scene/plot-point: somehow Inuyasha and Miroku are captured and held in this dungen/castle. There is some spell or sutra on the cuffs that keep them both chained to the walls that make it so that neither Inuyasha nor Miroku can use their strength or power to break out. When they find out what their (male) captor plans to do to/with them, I think it's Inuyasha who says something like: "We never the girls about this." Miroku: "Agreed."
I can't remember if there's a larger reason for holding them, But the guy who captured them was VERY interested in both of them. (as in; he was 'gunnen' for a little loven') And I think there even might have been some type of potion or elyxur to make Miroku more "maluble", when the time came.
The scene/plot-point ends with (I think) Inuyasha draggin Miroku out of the dungon just as Kagome, Sango, Kirara & Shippo are storming the castle.
I know that the above is part of a long, older fic. If absolutly ANY of this sounds even REMOTLY familiar, PLEASE let me know!!!