We've learned from Elmyra that Aeris has been captured by Shinra, who have been after the girl for years on account of her being an "Ancient". We decide to rescue her for reasons of loyalty and plot development.
Shinra's HQ is built in the middle of the wheel-shaped city of Midgar and stands far above the desolate slums where we've spent all our time thus far. Luckily, Shinra's villainous decision to drop the "plate" (the giant platform on which Sector 7's middle-class live) on to the slums, thus destroying them and all their inhabitants, has left a rickety pathway of architectural detritus leading directly to their corporate fortress.
But first, some backtracking, for local colour as much as anything else. We return to the Don's mansion, from which Aeris and I rescued Tifa only a few hours ago. There's a guy with a mohawk in the S&M dungeon. We set him free, without even knowing if we'll unlock some kind of minigame as a reward.