When Detective Moo Jin-hyuk's wife is killed, Kang Kwon-joo, an officer with great hearing, is on the other end of the 911 call. Three years later, the two 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.

When Go Dong-chul's death is ruled a suicide, Kwon-joo realizes she must take things into her own hands. Jin-hyuk hurries to find the victim, whom he knows personally, of a kidnapping case.

The clock is rapidly ticking for Kwon-joo as her captors prepare to bury her alive. Meanwhile, Eun-byul's own life is in danger as she's hidden in a location unknown to the police.

Kyung-il reveals to Kwon-joo that he witnessed her father's murder. Jin-hyuk and Kwon-joo go off on their own, feeling closer than ever to finding the perpetrator.