"Detective Investigation Files" revolves around the professional and meticulous investigations carried out by a group of dedicated police officers. As they delve into mysterious deaths with unclear causes, they tirelessly work towards maintaining peace and security for the people. However, their demanding job often comes at the expense of personal happiness. Cheung Dai Yong, a brilliant and astute police officer, has a track record of solving crucial cases. His trusted colleague, Lee Chung Yee, stands by his side, and together they tackle challenging and complex cases. Amidst their work, Dai Yong encounters Ko Jit, a tenacious journalist. Despite their initial conflicts, a deepening connection blossoms between them. However, Ko Jit already has a romantic partner.

Martial artist Ron Hall stars in this dark vampire thriller reminiscent of BLADE. Ambitious cop Derek (Hall) is dogged by a phobia that is unfortunate in his line of work. Having witnessed his father's murder as a young child, he is deathly afraid of blood, but when he takes the law into his own hands to catch underworld counterfeiter Gustoff Slovak, he is forced to face his fear. The operation blows up in his face, resulting in a massacre that leaves Derek the only one of his team to survive. Derek reaches the shocking conclusion that Slovak is actually a vampire, and joins forces with the last in a long line of vampire hunters, Master Kao, who agrees to train Derek in his ancient art. However, in order to combat Slovak--whose past intersects with Derek's own in disturbing ways--Derek must become that which he hates the most: a vampire.