Try something like:
(You need to mark every riddle line to start with: Riddle
on *:TEXT:!riddle:*:{
/msg $nick $read(riddle.txt, s, Riddle)
/timer 1 10 /msg $nick $read(riddle.txt, $calc($readn + 1))
}
Not tested, but that should do the trick.
riddle.txt should be setup like:
Riddle This is the actual riddle
Answer to riddle
(ty collective)