When Detective Moo Jin Hyuk's wife is brutally murdered, Kang Kwon Joo, an officer with superior auditory abilities, listens on the other end of the 911 call. Three years later, Jin Hyuk and Kwon Joo find themselves working together.

Jin Hyuk rushes to get to Bok Rim before it's too late. Kwon Joo compiles officers with varying expertise for her Golden Time Team.

Time is running out for Ah Ram as Kwon Joo tries to decipher the xylophone sound. Kwon Joo tells Jin Hyuk her side of what happened three years ago.