I'm trying to find two fics. One is Timcentric and the other is Tim & Jason centric.
- Tim centric - Tim is on an undercover mission involving street drugs but he ends up getting amnesia. He starts living with another kid who is part of a group who is being used by the drug ring (the kids are getting paid to transport the drugs to crime alley or the narrows or someplace like that). The only other things I can remember is that he uses one of his alias names (I think Jack or Alan) and they have a run in with red hood and some other batfamily members who have been looking for Tim (but because Tim doesn't remember them, he ends up running from them instead).
- Tim & Jason - The only thing I remember from this fic is that Tim and Jason are fighting a villain in an abandoned house in Gotham and get hit with a ray gun that transports them back in time or to another dimension (can't remember which). I also recall that Jason's helmet gets crushed in the fight as well and I think he was injured for part of the story. There was some sort of plot point involving the helmet (I think Jason kept explosives in the helmet?). I also recall a hospital being one of the settings but I'm not 100% sure.
Sorry I'm a little hazy on the details but I think they were both on AO3 but I could be wrong.