I need some help with my Pathfinder campaign idea - feel free to use it as well.

I'm planning to start my characters "waking up" at a table in some tavern basement. They all look at each other and have no idea who each other are and how they ended up there. The room is locked from the inside and there are several numbered and sealed letters on the table. (I'll use actual letters for the players to open and read)

At first they have to manage with the general situation - I'm pretty sure at least one of them will freak out in some way, because it's pretty fucked up to suddenly sit in some basement with guys you don't know.

additionally to the letters there's a small note that states: "only open a letter if you're told to. this is of utmost importance. you're memories have been stolen, but you have planned for this and you can trust each other. open letter 1 now."
on the bottom of the note are signatures of all characters. some of them even wrote a small line like: "I know. But you can trust them."

one of the characters (the lawful good one) realizes that he wrote the note (as well as the letters as the story unfolds)

I expect them to open letter 1: "The local academy of mages plans something you can't know for now. They have stolen your memories, but you must get them back. The academy is protected by a powerful barrier, but you should be able to get through it. Leave all your weapons behind, including all items that can be used as weapons, and place them into the ritual circle in the corner of this room. Take the letters with you and open letter 2 once you're inside. Make sure no one outside this group reads any of the letters."