The cause of the sinking of the Sewol ferry has been investigated over a long period of time and with the participation of numerous experts. This has resulted in several official announcements, but many bereaved families and other people involved are not convinced. The external force theory, that the ferry was tilted due to a collision with something else, was regarded as a conspiracy theory, and the people and groups who questioned the government’s announcements were labeled as bad eggs. 10 years after the sinking, Zero-Sum is a documentary that once again raises questions about the cause of the sinking of the ship, which has yet to be fully established. Those who participated in the 2nd and 3rd Sewol committees, the bereaved families, civilian divers, and journalists who were at the scene at the time, raise numerous suspicions that are still yet to be allayed. The same goes for former anchor, Son Seok-hee, who presented daily news at the time of the disaster. Yoon Solji, who has made documentaries about the Sewol ferry tragedy, including A Bucket List of a 17 Year Old Boy (2015) and The First and Last Minute of My Life (2018) suggests exploring the truth of the disaster once again without bias, rather than raising specific theories about it. (MOON Seok)