Even though there are books of answers and traditional answers to koans, there are no answers. Your answer comes from your mind not someone elses.
Asking what the answer to a koan is demonstrates that you should reexamine what the purpose of a koan is.
The have a "proper" answer set out for a koan would undermine its function as a training device in the instantaneous appreciation of the whole and reduce it to an intellectual exercise like solving a math problem. Review Robin Williams' discussion of the analytical review of poetry in "The Dead Poets Society"
In this case, to answer "Nothing" would made "Nothing" "Something" and be contrary to the basic premise of the question. A suitable answer could be "Roses on a bush", but only if you understand why.