Serina arrived at school one day to discover someone had scribbled the lyrics of a love song all over her desk... and the culprit turned out to be one Mizukawa-sempai, a boy one year her elder. He was awkward at first, but Serina was too intrigued not to pursue him. Before she knew it, she'd asked him out -- and now they're well on their way to their next step as a couple. After Valentine's Day comes White Day! The new school year is just about to start, and Serina and Mizukawa-sempai find themselves that much closer. But you'll never guess who's in her class this year!! With each passing second, Serina's heart beats a little faster!