Boku wa Chikyuu to Utau: BokuTama Jisedai-hen II

Four years have passed since Boku wo Tsutsumu Tsuki no Hikari. Ren has grown up and is now in 6th class of elementary school. While he is coping with emotional issues over being a Kiches, brooding over his one sided love and not being able to see his "Guardian Angels" anymore as the only one in his family, a mysterious girl appears before him and later in dreams before Rin and the other reincarnations from the Moonbase, trying to get their Moonbase passwords...