Hyper-Kamiokande (Hyper-K) succeeds the very successful Super-K experiment and will consist of a large detector filled with 260 kton purified water and equipped with 40% photo-coverage. Physics program of Hyper-K is broad, covering from particle physics to astrophysics and astronomy. The Hyper-K 1$^{st}$ detector will be built in Japan, and the 2$^{nd}$ detector is considered to be built in Korea because locating the 2$^{nd}$ detector in Korea improves physics sensitivities in most cases thanks to the longer baseline ($\sim$1,100km) and larger overburden ($\sim$1,000m) for Korean candidate sites. In this talk, we present overview and physics potentials of the Hyper-K 2$^{nd}$ detector in Korea.