Despite belonging to a family of four, the Aoyama residence is typically home to three, with Dad away for work. Mom Tomoko and her two darling sons, Hiroki and Yuri, go about their everyday lives with little to disturb their gentle routines.

But as Hiroki begins his first year of high school, Tomoko can't help but wonder if her eldest has fallen for another boy. Though Tomoko is content to cheer on her son from the sidelines and let him work things out for himself, Hiroki's slips of the tongue are hard to ignore! With little talent for keeping his "secret," Hiroki might just die of embarrassment before all is said and done!