You had managed to track down the Scarecrow, he was terrorizing Gotham again and the entire Batfamily was after him, until you found him. Maybe it was overconfidence or you let your guard down, but before you knew it, the Scarecrow dropped a bomb of his fear toxin towards you.

"Nice try, but you can't run away from fear." You hear Scarecrow say.

Fear toxin floods your lungs before you can react, you blink and you're in the dark, surrounded by your worst fears.