Crisis Core: Final Fantasy VII/08: See You Soon

This chapters starts in Nibelheim. The walkthrough assumes that you did everything (so if you don't receive a mail when it's mentioned in the walkthrough for example, it's surely because you missed something).

Nibelheim
Approach Sephiroth for a cutscene. Then, don't talk to him just yet, instead, take a look at the Side Quest Seven Wonders Expert. In any case, you will need to enter the Inn, so go talk to Sephiroth after you've uncovered the first secret. Talk to Cloud, he doesn't seem to want to be recognized here...

Inn
You will receive a mail from Cloud. Before talking to Sephiroth, I would advise to follow the Seven Wonders Expert Side Quest until you need to talk to Sephiroth (it's required to progress in the Side Quest at some point). In any case, talk to Sephiroth.

Mako Reactor
After a cutscene, you will be able to move again, talk to Sephiroth for another cutscene.

Reactor Entrance
After the cutscene and the fight, grab the chest near you. Then, go to the south.

Trail
When you arrive at a crossing, take a left, there are 3 chests (one near the beginning, 2 at the end).

Outskirts
There is a chest to the east near houses.

Inn
After the cutscene, you'll wake up at the Inn. Talk to Cloud and get out. You'll receive 2 mails along the way. Before you reach the door, another tiny cutscene will play, and you'll receive a mail from Red Leather.

Nibelheim
Move towards Cloud to start a cutscene, then, talk to him and follow him.

Outskirts
When you will approach the manor, you'll receive several mails.

Shinra Manor
Talk to Cloud and climb the stairs, there will be a chest and you'll receive another mail from Luxiere. Upstairs, go to the right, and you'll receive a mail from Tifa. Approach the South-East room, talk to Cloud, and then open the door to the Underground Cave.

Underground Cave
There will be a chest in this room. Now go down the ladder. Two of the rooms here contain 2 coffins each, it is tied to the fifth mystery of the Side Quest Seven Wonders Expert. In each room there is also a chest. Before going to where Sephiroth is, I'd advise to do the first 5 mysteries of the Seven Wonders Expert Side Quest. You should also make a separate save just in case. Anyway, go find Sephiroth. THIS IS ANOTHER POINT OF NO RETURN, especially for the Side Quest Seven Wonders Expert,

Basement Facility
After the cutscene, leave the library to find a chest containing an Elixir, then leave this room too.

Nibelheim
Look behind you to find a chest, then, if you were at the 6th mystery of Seven Wonders Expert, talk to the little boy and follow the instructions from the Side Quest page. Then, just continue. You will find Cloud on the ground to the right, and then you'll get a cutscene. After this, progress to the next zone.

Trail
You'll receive a mail from Cloud (is he dumb? we already know the town's on fire because of Sephiroth, we just talked to him...). Anyway, continue towards the reactor.

Reactor Entrance
Just continue towards the reactor.

Reactor
Approach Tifa for a cutscene.

After the cutscene, it's time for another boss fight:

Unfortunately, this isn't even his final form!

After the fight, another cutscene and the chapter will end.