Synopsis

“Killer Number 4” is a co-production between Hong Kong and Japan with Sakamoto Yugo of “Baby Valkyrie” working on the script.
 
This action-packed thriller centers on “No.4,” a professional assassin based in Hong Kong. One day, he receives a lucrative ¥100 million contract requiring him to travel to Japan and eliminate yakuza boss Kumagai. After successfully completing the mission, he encounters Kumo, a young woman claiming to be his client.
 
The film follows two individuals who share tragic pasts – both having witnessed the brutal murder of their families. Through their journey, they forge a deep bond as master and apprentice in the deadly art of assassination. As their relationship evolves from master and apprentice to trusted partners, the duo ultimately face a formidable enemy together as an unstoppable team.