Namgang Police Station's Traffic Crime Investigation Team cracks down on a second-hand car crime ring. Insurance investigator Cha Yeon-ho who mistakenly gets arrested with the criminals, and hands over a suspicious envelope to TCI leader Min So-hee.

The TCI members arrest an insurance fraud suspect, but must release him due to a lack of evidence.

TCI sets out to catch the ghost that causes traffic accidents at the Ganghui Three-Way Junction. Yeonho finds out that these accidents frequently occur on rainy days due to road defects.

While investigating a hit-and-run case, TCI learns that it is tied to auto theft.