Employees at a police station and a fire station work together to solve cases. Jin Ho-Gae (Kim Rae-Won) works as a detective. He does his job well. He isn't friendly when he talks to people, but he solves cases with his excellent ability to grasp crimes scenes, read a criminal's mind and having a strong will to win. Bong Do-Jin (Son Ho-Jun) works as a firefighter. He is enthusiastic with his work. He seems cold to people, but he is nice to those around him and he takes good care of victims. He rushes to fire sites without a moment of hesitation. Song Seol (Gong Seung-Yeon) works as a paramedic. She has a warm heart.