Refers to television dramas from South Korea, often associated with the Korean Wave (韓流).
See also: 韓国ドラマ
I've been hooked on Korean dramas lately.
This K-drama is very popular in Japan as well.
Compound of 韓流 (Korean wave) and ドラマ (drama). 韓流 itself is a Sino-Japanese word coined in the late 1990s to describe the surge in popularity of South Korean culture.