Kill it

Kim Su-hyun was raised as a killer in a foreign soil after being abandoned by his father when he was 11 years old. One day, he returns back to Korea while chasing his target, and perfectly disguises himself as a warm-hearted veterinarian. When he moves to a new house, he meets his neighbor Doh Hyun-jin, a police detective who lost her first love while investigating a mysterious case. The unlikable pair get along well, and Su-hyun's secret life starts to get revealed, while Hyun-jin slowly starts to fall for him.