  NOvA is a long-baseline accelerator-based neutrino oscillation experiment
that is optimized for $\nu_e$ measurements. It uses the upgraded NuMI beam from
Fermilab and measures electron-neutrino appearance and muon-neutrino
disappearance at its Far Detector in Ash River, Minnesota. The $\nu_e$
appearance analysis at NOvA aims to resolve the neutrino mass hierarchy problem
and to constrain the CP-violating phase. The first measurement of
electron-neutrino appearance in NOvA based on its first year's data was
produced in 2015, providing solid evidence of $\nu_e$ oscillation with the NuMI
beam line and some hints on mass-hierarchy and CP. This talk will discuss the
second $\nu_e$ oscillation analysis at NOvA, which is based on 2 years of data.
