  The negatively charged nitrogen-vacancy defect (NV)$^-$ in diamond has
attracted much attention in recent years in qubit and biological applications.
The negative charge is donated from nearby nitrogen donors that could limit or
stem the successful application of (NV)$^-$. In this Letter, we unambiguously
identify the \emph{neutral} nitrogen-vacancy defect (NV$^0$) by \emph{ab
initio} supercell calculations. Our analysis shows that i) the spin state can
be \emph{selectively} occupied optically, ii) the electron spin state can be
manipulated by time-varying magnetic field, and iii) the spin state may be read
out optically. Based on this NV$^0$ is a new hope for realizing qubit in
diamond \emph{without} the need of nitrogen donors.
