Sonata with The Shadows

Lucas Calspec feels like the luckiest demon to have ever lived. Dating the most beautiful demon in all of Exfa, Althea Sonata, he feels as if it's a dream come true. Sadly, dreams come to an end and nightmares replace, as he becomes worried about his new partner over the infamous secrets he knew about the Sonata family. Running away with her, every family member is on the chase to get her back. What are their secrets? What is the reason behind all this? Is this love too good to actually kill them both? Or will both be alive to live a normal life?