Lily is always along with Sen and Annie. They go to school together, join the guitar club, and share the same youth. Hopefully that their friendship could last ever after. At the same time, Lily found that her feelings for Annie seem to have changed. One day, Sen is going to immigrate. However, Lily is too late to tell the secret to Sen, she makes every effort to seize the days. On the last night, Lily and Sen decided to stay at the campus overnight. Accidentally, Lily found a regret left behind by Sen.