A Manhandled Manservant

 is an unmarked Fallout 3 quest.

Argyle has not been seen since he was separated from Herbert "Daring" Dashwood on their escape from Rockopolis. The retired adventurer refuses to believe his manservant died in that battle though, instead believing he is still out there somewhere. Upon visiting Rockopolis and finding Argyle's corpse, the player may return the news to Herbert Dashwood at Tenpenny Tower for a reward.

Dashwood, sad to hear of Argyle's demise (he always thought Argyle would outlast him by at least 100 years), tells the player that his days of adventuring are over and gives the player the key to his safe.

Rewards
Inside the safe are Bottle caps, Mentats, a Mini-Nuke, Rad-X, Schematics - Bottlecap Mine, a Stealth Boy and Stimpaks. IMPORTANT: Taking the Bottle caps will result in him turning hostile towards you. (edit) only if you do it in front of him, for some reason even though he gives you the key it still counts as stealing, and he will react as such.

Bugs

 * Although Dashwood will give you the key and permission to access the contents of the safe, he will attack you if he sees you looting while the safe is still "red" as a result of this bug. This may also result in a loss of karma as it is considered theft, even though Dashwood said otherwise. This bug is mainly associated with the bottle caps in the safe. Looting everything else in the safe will not turn Dashwood hostile. A workaround is to use the setownership command through the console before opening the safe so you don't take the negative karma impact.
 * Attempting to remove ANY item in the safe resulted in Dashwood yelling "Thief!" and turning hostile. Stealthing before taking anything avoids Dashwood turning hostile, but still triggered bad karma. (XBOX 360)