Maru (Yuki Maruoka) is an honest, straightforward girl inexperienced when it comes to love. One day, she becomes witness to a groping incident on the train. She goes up to confront the offender, but not before a handsome, young fellow nearby calls him out for his actions. The two somehow manage to drive the man away. But right afterwards, in a baffling turn of events, the boy asks Maru to go out with him. Although Maru, flustered, rejects him in the spur of the moment, she slowly becomes drawn to his kind and sincere personality. She then discovers that he's an older student attending her high school, also known by some as "Mr. Perfect"! When she finds him again to apologize, she inadvertently ends up blurting out, "Why don't we start as friends"? A sugary sweet romantic comedy following the antics that ensue between Maru and a mature, older boy in school solely focused on winning her heart, showering her with special attention and kindness at every chance he gets.