Mizuki Sarashina's a new employee at a company and her mentor's a guy rumored to be "cool and handsome"... No, he's named Hyogo Kishima and he has the nickname of "newbie killer"...!!Mizuki has a strong fighting spirit and manages to keep up with the workload he gives her. Then, one day, Mizuki finds a piece of chocolate on her desk and doesn't know where it came from...From the one-off story "Dangerous Pranking During a Secret Office Romance" comes the return of the ever-fighting couple! This is the start of a new series where we find out how Mizuki and Hyogo first met!