Iony的新曲[Spring letter]是具有快节奏的温暖气氛的歌曲，是向单恋的对方告白的歌曲. 该剧表达了画家希望像春天一样开始爱情的心意。 作词、作曲和编曲由Iony参与，主唱则由与Iony一直保持良好合作的歌手Jung Mi参与，提高了完成度。 Composed by Iony(아이오니) Lyrics by Iony(아이오니) Arranged by Iony(아이오니) Song by 정미 Piano by Iony(아이오니) Recorded by Iony(아이오니) @Vamos Records studio Mixed by Iony(아이오니) @Vamos Records studio Mastered by Iony(아이오니) @Vamos Records studio Executive Producer Vamos Records Music Producer Iony(아이오니) Planning & Marketing 임성우, 이유정, 이휘원 Administration 김지현