One Good Turn Deserves Another

One Good Turn Deserves Another is an optional side quest in Deus Ex: Human Revolution.

Meet with Greg Thorpe
This quest is initiated by reading Adam Jensen's email if he saved both Greg and Josie Thorpe at the Milwaukee facility.

The email states that Greg will like to thank him and to visit them at their home in their apartment building, behind Grayson's gas station.

After traveling there and speaking with Greg Thorpe, he tells Adam about a weapon dealer named Seurat and to use Greg's name when dealing with him, this will give Adam a discount when purchasing weapons from him.

This completes the quest and awards 750 xp.