The Amazing Aqua Cura!

 is a Fallout 3 quest that is added to the game in the Broken Steel add-on.

Walkthrough
This quest can be started by hacking Scribe Bigsley's computer in Jefferson Memorial and looking through the logs, a successful Speech check with Bigsley, or by talking to Griffon himself in the Museum of History.

Griffon, a ghoul outside of the Underworld, is selling Aqua Cura (which is basically just dirty water, claiming that it will cure the Ghoul condition. You learn that he buys Aqua Pura from Bigsley and replaces it with Dirty Water, re-branding it Aqua Cura in the process.) After getting a bottle from him you can confront him with the fact that your Pip-Boy 3000 detects the water being irradiated; he will deny it and call your claims accusations without proof.

Find Griffon's bottling operation
To find proof, you need to find Griffon's bottling operation. Naturally, the ghoul salesman himself does not want to tell you where it is. However, as he mentioned that Scribe Bigsley's men deliver the Aqua Pura to him, Bigsley likely knows where it is. Arriving at Jefferson Memorial, the scribe will freely tell you that Griffon's operation is in the Museum Authority Building. When you first enter the building follow the hallway on the left to the northwest corner of the ground floor and go down the stairs. When you go downstairs take a right into a big room with barrels and tubs. In between 2 tubs on a coffee table are 2 Dirty Water, a Nuka-Cola, a Clipboard, and a holotape. The holotape tells you that Griffon's Ghoul Guards dump the Aqua Pura into the tubs and sinks, selling that to raiders and slavers while he sells dirty water in aqua cura bottles to ghouls.

Dealing with Griffon
When you go confront Griffon you have three options: blackmail him, force him to tell the truth, or force him to sell real Aqua Pura from that point on.
 * It should be noted if there are no effects to Karma with each of the three options.

Blackmailing Griffon

 * You can blackmail him for 300 caps, 160 caps every week, or 400 caps every week if you pass a speech check. (It is possible this is a reference to iguana Bob in Fallout 1)

Forcing Griffon to confess
If you force Griffon to confess about the true nature of Aqua Cura, the crowd will turn hostile against him and:
 * Griffon will attempt to defend himself, but ultimately run away and hide in one of the bathrooms at the entrance of the Museum of History. The crowd will follow him into the bathroom where Griffon will make a final stand but is eventually killed by the angry mob.
 * He may be killed by the mob at other locations in the Entrance area. He may also escape the mob and flee through the doors to the Lower Halls.  The mob will follow him, but they disappear after entering (apparently they can exist only in the Entrance).  Griffon will be just inside the Lower Halls with gun drawn and will remain there as long as the player is nearby.  He eventually disappears from the area if he is not killed by the player (Xbox360).

Selling the real Aqua Pura
Although Griffon will tell you to come back in a week, his dialogue will remain the same, simply informing you his business with you is concluded, then try to pass you off as a happy customer to the crowd.


 * If you chose to add the Modified FEV to Project Purity, then The Chop Shop will be full of ghouls suffering from its effects.

Bugs

 * If you have completed this quest and left Underworld, attempting to return may cause the game to crash. This is very bad if you have entered the Feral Ghoul part of Underworld, as there is no way out except for the Museum Lobby (confirmed Xbox 360)