"Mouse: The Predator" reveals the serial murder from the perspective of the Predator, in order to help the audience understand the hidden narrative, before entering the second part of the story. These episodes will highlight the hidden narratives in the series that the audience may have missed. (Source: IMDb, Wikipedia) ~~ More than 80% of the content in spin-offs was not aired in the previous episodes. The spin-offs were first released on the online platform TVING at 16:00 (KST) on April 28th, followed by television broadcast.