Kasuhara Yuki is a command and control officer in Section 3 of the Yokohama City Fire Department's Command Section. She used to work in a bank, but one day, she passed the firefighter recruitment test, and after two years in the field, she voluntarily requested to be transferred to the Command Section.

The Command Section is where personnel respond to 119 calls and dispatch ambulances and fire engines when appropriate. These personnel's job is to listen to voices and save lives in crisis, but they also have to deal with prank calls. They are also required to be prepared for huge disasters and major accidents and are constantly exposed to extreme tension in their workplace.

Yuki has excellent insights and is the type of person who puts her thoughts into action immediately. However, she often gets pushed around by those around her and sometimes creates friction within the organisation when she goes to the accident scenes to check the situation herself after a call has been made.