Riftweald Manor
Riftweald Manor is Mercer Frey's residence in Riften. The front and back entrances bear the "Guild shadowmark". On the ground floor is a "suspicious cupboard" which is in fact a secret passage leading to a series of underground tunnels and Mercer's secret room.
In the room are Mercer's Plans, the Bust of the Gray Fox, and a weapon case which holds Chillrend. There is also an entrance to the Ratway which bears the "Danger shadowmark".