Akira Tachibana is a soft-spoken high school student who used to be a part of the track and field club but, due to an injury, she is no longer able to run as fast as she once could. Working part-time at a family restaurant as a recourse, she finds herself inexplicably falling love with her manager, a divorced 45-year-old man with a young son. Despite the age gap, Akira wholeheartedly embraces his mannerisms and kind nature, which is seen as spinelessness by the other employees, and little by little, the two begin to understand each other. Although unable to explain why exactly she is attracted to him, Akira believes that a concrete reason is not needed to truly love someone. On a rainy day, she decides to finally tell her manager about how she feels... but just how will he react?

Imagine being the only child your whole life, and then suddenly finding yourself gaining 13 step-brothers! Ema Hinata's lonely life takes a new and exciting turn when her single father Rintarou Hinata, a famous adventurer, falls in love and marries Miwa Asahina, an apparel maker. In order to give the newly-wed couple space, Ema starts living with her new step-brothers in a mansion called Sunrise Residence and for the first time, experiences being part of a lively and big family. She finally feels safe and content. Each brother has his own unique personality, and Ema soon realizes that it is not only family love that grows between them, but romance as well. Which brother will be the one to steal her heart in the end?