Nobuko "Mobuko" Tanaka is not the type of girl to stand out in a crowd. Shy and often overthinking every situation, she has led a life with as little social interaction as possible. As a result, it seems like an impossible task for Nobuko to confess her feelings to her coworker Hiroki Irie, a reserved young man who helped her when she first started her new job at the supermarket.

However, after witnessing her junior colleague Abe exchange contact information with him, she finally summons up the courage to ask Hiroki for his number. Despite her timid nature, this one act of determination sets Nobuko on the path to becoming the protagonist she has always wanted to be while her budding romance slowly begins to blossom.