An 18-year-old young man who lived a peaceful and normal life is murdered by an unknown man. He is reincarnated as an evil little dragon who is the pet of the crown prince of a magical kingdom. He discovers that the prince is actually his reincarnated assassin, and that he has a secret mission to destroy the kingdom. The little dragon will have to face the dangers and intrigues of the royal court, while at the same time trying to get closer to the prince and discover his true feelings. Will he be able to stop the prince's evil plan and find his happy ending?