Boku wa Chikyuu to Utau: BokuTama Jisedai-hen II  

I Sing With Earth, ぼくは地球と歌う ―ぼく地球 次世代編II―, Boku wa Chikyuu to Utau: BokuTama Jisedai-hen 2

Four years have elapsed since Boku wo Tsutsumu Tsuki no Hikari. Ren is currently enrolled in 6th grade at elementary school. Despite grappling with emotional turmoil related to his status as a Kiches, dealing with unrequited love for someone who doesn't feel the same way, and feeling disconnected from his "Guardian Angels" since they are no longer present in his life as the only family members, an enigmatic girl emerges before Ren and later appears in dreams shared by Rin and other reincarnations residing on the Moonbase. The mysterious figure seeks to obtain their respective passwords for accessing the Moonbase.