Tiffany Hwang is a private investigator working for her father along with Kim Taeyeon solving crimes, but has something special. She has super memory which means when she sees something once she will remember it forever. 

Jessica Jung is a police officer under her boss Choi Sooyoung and works alongside Lee Sunny. Until one day, Jessica Jung gets accused for murder but she keeps denying saying she never did the crime.

The police have a video of what it seems like her walking through the crime scene

Did she commit it or someone else?