The predissociation of the ${\mathrm{N}}_{2}{}^{+}$ molecular ion in the $C {}^{2}{\mathrm{\ensuremath{\Sigma}}}_{u}{}^{+}$ electronic state through the nonadiabatic coupling with the $B {}^{2}{\mathrm{\ensuremath{\Sigma}}}_{u}{}^{+}$ electronic state is studied by solving the Schr\"odinger equation. The predissociation rates are calculated using Fermi's golden rule and compared with experimental results. We characterize the dynamics by calculating the nuclear probability density $\ensuremath{\rho}(R,t)$, the nuclear flux density $j(R,t)$, and the two-electron flux density $\mathbf{j}({\mathbf{r}}_{1},{\mathbf{r}}_{2},t)$. It is found that at the early dynamics, $t\ensuremath{\le}100$ fs, Fermi's golden rule breaks down, while a strong correlation between the electronic and nuclear dynamics is observed. Fourier analyses of the probability and flux densities are also presented and yield insight in their frequency dependency.