7 Months Ago, Mygamer.com says (in Elder Scrolls Novels Announced)  NJ - Zachary Gasiorowski
The Infernal City is set after the events of The Elder Scrolls IV: Oblivion, the latest game in the video game series, and finds the citizens of Tamriel once again facing an uncertain future. Floating high above the land is a strange and mysterious ...

And CVG Online says (in 2 Elder Scrolls novels confirmed) The Infernal City is set after the events of The Elder Scrolls IV: Oblivion, when a mysterious city floating high above the land is casting a horrifying shadow that's causing people to die and rise again as undead.

And Spong says (in Star Wars Author for Elder Scrolls Novels)  UK
The official bumph tells us, "The Infernal City is set after the events of The Elder Scrolls IV: Oblivion, the latest game in the video game series, and finds the citizens of Tamriel once again facing an uncertain future. "Floating high above the land ...