Plagued by low self-esteem and social anxiety, eighth-grader Hikage Sumino has gone unnoticed throughout her life. When she started middle school, she resolved to make friends, yet by the end of her first year, her efforts have yielded no results. Her sole solace comes from a solitary flower she discovered and tends to regularly, as well as "1 Centimeter of Happiness," her sunflower-themed internet blog where she frequently shares her thoughts and experiences. Although her blog typically attracts only two visitors, Hikage derives satisfaction from their comments and values their support. One day, she is startled to discover that Hinata Mutou and Teru Mikami, two of her school's most popular boys, are aware of her existence and recall her name. Stunned by this unexpected revelation, she writes about the encounter on her blog and receives an inspiring comment from one of her regular readers. Following the advice of her online friend, she builds some confidence and hopes to improve her world.