Dear Experts

While I was reading the story in the link blowe : /

I came across this quote
"Had it not been for their quick thinking, it would have been a different story,"
I feel there is a typo ,,,,missing "if clauses"

If someone shed any light on this I would be grateful ?

The 'if' clause has an alternative structure:

Had it not been for = If it had not been for.
Thanks for that.

Edit : I just realized that the question below is realted to my thread as well

"Had it been" means "If it was/were"