The third trailer for The Chaser initially seemed like a simple compilation of the first and second trailers. Given that a movie has only so many scenes it can reveal—especially in a thriller where too much exposure can detract from the immersion on release day—the first two trailers had mainly focused on the masked killer in the raincoat and the police chase. The identity of the victims was not even clearly shown.

But then came the final ten seconds.

• Ju Seoyeon is the killer???
• What’s going on?
• Wasn’t she just the convenience store clerk?
• I knew it. Why else …