A plot could revolve around a character from the past in the Twilight world, like a long - lost vampire ancestor, who is awakened and immediately falls in love with a modern - day character. Their love is not bound by time and they strive to be together despite the many differences in their eras, including different social norms among vampires and different relationships with other supernatural beings.
Maybe a story where a werewolf and a vampire, who are supposed to be enemies in the Twilight universe, fall in love. They have to fight against the prejudices of their respective packs and covens. Their unstoppable love might lead to a new era of peace between the two groups. For example, they could work together to protect their territory from a common external threat, which also deepens their bond.