Your sentence was not added because the following already exists.
This English is remarkably vague. I don't think it fits the Japanese so well. Perhaps something else would be more suitable?
"There is a clear deadline to return the book."
"There is a deadline to return the book."
"There is a definite deadline for returning the book."
Thoughts?
P.S. The current sentence, in my view, has a connotation of something like, "You must return the book between 5 and 6 this Tuesday, because that's the only time returns are allowed." But even that is guesswork.
