FL is worried for her child and manages to escape during a blizzard while ML is away from their Castle. Ml comes back, goes berserk and starts chasing after her out of anger- feels betrayed that 'his property' has escaped. The princess runs into an actual dragon during her escape- there's a lot of backstory about how the dragon had a human lover and he tricked her to teach him magic then ran away back to his human lover... The dragon believes interspecies relationships are doomed but transforms into a human to follow the princess and see how her story will play out. It also grants FL the ability to cast magic (before she only had huge magic reserves but was unable to use them by herself without her brother)