Agatha's Song

 is a Fallout 3 quest. It is also an Xbox 360 and PC achievement.

Retrieve the Soil Stradivarius from Vault 92 for Agatha, an old woman living alone in a house in the Capital Wasteland

Meeting Agatha
Her house is west of the Scrapyard and can be tricky to find since it is surrounded by rock piles except for the small passage from the west over a suspension bridge. If you are having troubles finding it, then look for caravans in the area with your Pip-Boy since they are often positioned right in front of the passage to her house.

Agatha is a talented violin player who broadcasts her music through her late husband's old radio gear. She wants the you to find her great-great-grandmother Hilda's Soil Stradivarius violin, which she believes is still in Vault 92. She doesn't know the location of the vault, but if asked can give you the location of Vault-Tec Headquarters on your Pip-Boy. At this point, going to Vault-Tec Headquarters is entirely optional. You can get the location of the vault while doing the quest Picking up the Trail or just by stumbling on it.

Locate Vault-Tec Headquarters (Optional)
There's several ways to reach Vault-Tec Headquarters.
 * Travel to Vernon Square Station from Chevy Chase East. From GNR go through the abandoned school, through the corridor, and past the super mutants. There You will find Chevy Chase North Station across the street, don't go that way. Instead, hang a right and follow the road a very short distance to Chevy Chase East. Once inside the station go down to the metro rail and follow it a bit until you reach a sign that says <---GNR Radio Metro Mall--> go left toward the mall. Stay on the tracks and go under the upper platform, till you reach a service door on your left. It is the only way you can go, enter the service door, exit the station, and poof, you are in Veron Square Station. You can also find Our Lady of Hope Hospital and The Statesman Hotel in this area. Go North/Northwest until you reach Vault-Tec Headquarters. This path involves a certain amount of resistance from Super Mutants in the Vernon Square area.
 * Travel to Chevy Chase North and from there find your way through the subway tunnels to Vernon Square North. The Vault-Tec Headquarters should be directly to your left when coming out of the station. Note that this probably involves the less amount of fighting in Vernon Square as you'll be close enough from the building to avoid the Super Mutants.

Discover the location of Vault 92 (Optional)
Once inside Vault-Tec Headquarters, make your way to the Vault-Tec Mainframe. The building is divided into 3 sections. The Guest Relations (Lobby), the Corporate Offices and the Administration. The building is still protected by several automated units such as Protectrons, Robobrains, Turrets and depending on your level and the game difficulty level Sentry Bots. There's also a few remaining Super Mutants when you come in, but they seem to have their hands full.

The Mainframe is located in the Administration section. To gain access to it, you will need to obtain permission from System Operation Station 1, 2 and 3. The terminals are scattered across the Administration. Once you gain access to the Mainframe, you'll be able to download the location of Vault 87, Vault 92, Vault 101, Vault 106 and Vault 108 on your Pip-Boy.

Recover the Soil Stradivarius from Vault 92
Vault 92 itself is infested with Mirelurks, Mirelurk Hunters, Mirelurk Kings, Bloatflies, and Radroaches. The Soil Stradivarius is located in the Sound Testing section of the vault.

Entering the vault, the first room should have 3 doors. The door in front of you should lead to the Atrium, the door on the left should lead to either the Classroom or Lab. The door on the right is unmarked and leads to the Living Quarters. If you can unlock average doors, enter the door on the left, otherwise you'll need to go around through the Living Quarters. Once you're upstairs in the atrium; you should have a door to the Reactor section and an unmarked door that leads to the Sound Testing section.

In the Sound Testing area, take the corridor on your right. Find a staircase with the sign Lab above it leading down. This should be immediately to your right if you came in from the Atrium, to your left passed a corridor if you came in from the entrance. There are two Mirelurk Kings down there, so be careful. Down the staircase, you'll come to a 3-way intersection. To your right there should be a room with a Mirelurk King, a juke box and a soda machine. To your left, you should see a T-intersection. You'll need to unlock the music studio in order to get the violin. The terminal to grant access to the music studio (with the other Mirelurk King) is in the room to the left of the T-intersection, the violin is in the room to the right.

Return to Agatha
Upon completion of this quest, Agatha will give you the frequency to her radio channel for your Pip-Boy. It plays violin music and can be heard across the entire wastes.

If you bring Agatha back a Sheet Music Book, which can be found in Vault 92 and several other locations (see: Sheet Music Book), she will give you the Blackhawk, a unique, modified .44 Scoped Magnum and 12 .44 magnum rounds that was her husband's property. To get the Blackhawk, you must ask for the reward (second option). Watch out, if you're rude towards Agatha your Blackhawk's condition will be halved. If you don't have any Sheet Music Book when talking with Agatha again, she'll tell you that she needs Music Paper to write her music on and asks you to retrieve some for her.

Alternatives

 * You can bring the Soil Stradivarius to Ahzrukhal at The Ninth Circle in Underworld. If you tell him it's one of a kind, he'll buy it off you for 200 caps (or Speech him for 300 caps) and you will get the achievement for finishing the quest.
 * It's also possible to sell the violin for caps to Abraham Washington in Rivet City.