Eve no Nemuri

It's been 18 years since Rin died. Alisa, who is Sei and Lou May's daughter, lives with her mother, her brother Shinji, and Ken in Hawaii. Shinji is Ken and Lou May's son. Shinji knows Alisa isn't Ken's real daughter, but Alisa doesn't. Alisa sometimes sees a phantom boy. One day, she sees a boy point to the sky, where she sees a plane. By the plane, Rie, Shin's son, comes to ask Ken for some help. He also knows Alisa is really Sei's daughter. Alisa is called "Dragon's daughter." Rie says a prophet told him that he would marry a woman who's a dragon's blood relative. When they go into the forest, Rie also sees a boy. Alisa tells him that the boy is a phantom and that he is the only other person who can see him. Her family had told her that the boy was the spirit of the forest, but she doubted that. She thinks the boy is trying to tell her something.
(Source: Baka-Updates Manga)