Twilight Investigation(Traditional Chinese: 囧探查過界) is a TVB modern drama series.

Former police officer Yip Kwok Cheung ( Bill Chan ) has set up a private detective agency. The members of the team all have their own strengths, and Gei On Gui ( Wong He ) is one of the most important members. With careful thought and sharp deconstruction of dialysis , the team has investigated out and solved crimes.

Because of investigating an adultery case, On Gui is acquainted with the nameless teen-model, Chung Yee Tuk ( Linda Chung ). Yee Tuk was born in an incomplete family, and is withdrawn. This makes her frustrated in both love and work. One night, Yee Tuk was drunk driving, crashed her car into a tree, and died. This experience made her want to find her long-lost mother so she asked On Gui to help her. On Gui is sympathize with Yee Tuk and try his best to find Yee Tuk's mother, but during the investigation, he discover a secret of Yee Tuk's mother that even Yee Tuk doesn't know.