Overcome by her anemia, Saku Fujigaya falls unconscious and loses her precious handbag while disembarking from a crowded train. Upon waking up in an infirmary, she finds her bag and all its contents beside her, along with a note with only her benefactor's name and phone number. To her dismay, her calls never manage to connect.

Saku used to think of herself as a background character—someone whose presence would always go unnoticed. However, one person had gone out of their way to notice her predicament and come to her aid. Moved by such an act of pure kindness, Saku begins to change her views on herself and the world. Despite being ridiculed as a goody-two-shoes by those who merely stand by and watch, Saku makes it her purpose to assist everyone who needs or wants help—an ambition she carries into high school.

During her first day of high school, Saku thinks she hears someone calling her name, only to realize they are looking for a Sakura—the same name as that of her mysterious savior.

Included one-shot: Volume 5: Otome no Itari