A possible plot idea is that the baby is born prematurely. Mary and Francis are worried about the baby's survival. They turn to their most trusted advisors and physicians, but there are also those who see this as a sign of weakness in the monarchy. Meanwhile, there could be an enemy lurking in the shadows, planning to use the baby's fragile state to their advantage. As Mary and Francis fight to protect their baby, they also have to deal with the internal politics and power struggles within the court.
In fanfiction, Francis and Mary could face a magical threat together. Maybe a sorcerer has cast a spell on the kingdom, and they have to work together using their wits and courage. This would not only test their love but also show how they support each other in difficult times. It could lead to some really interesting character development and romantic moments as they rely on each other to save the kingdom.
Around the baby, Mary and Francis's relationship could change in many ways. They may become more protective of each other as they are now a family. Their relationship with their servants might also be affected. The servants who take care of the baby could become like family to them. Francis might become more understanding of Mary's insecurities as a mother, and Mary could see Francis in a new light as a father. Their relationship with the court could also be influenced. Some in the court might try to use the baby for their own political gain, which would force Mary and Francis to stand united against such threats.
Another plot might involve the baby having some sort of special gift or ability. This could bring both wonder and danger into their lives as they try to protect the baby from those who might want to use or harm it. For example, the baby could have an uncanny ability to predict events, which gets noticed by the wrong people.
Maybe in the fanfiction, Reign Bash and Kenna find a baby with special powers. They decide to raise the baby in secret while also trying to figure out the origin of these powers. As they do this, they face opposition from those who fear the baby's powers.
In 'Reign', Francis and Mary had a complex relationship. Francis was initially hesitant about their arranged marriage but grew to love Mary. For fanfiction, one could explore their early days, like how they first started to understand each other's personalities. Maybe a scene where they share a private moment in the garden, talking about their hopes for the kingdom and gradually realizing their feelings for one another.
Obviously, Mary and Francis are the main characters. They are the parents of the baby in this fanfiction.
Well, you could write a reign fanfiction that focuses on the younger years of the main characters. For example, what was Mary like as a child in France before coming to Scotland? You could also do a story about how the political alliances in the show might have been different if certain characters had made other choices. Maybe a fanfic where a character from a different historical era somehow gets transported into the reign universe and causes chaos or helps in unexpected ways.
There might be a fanfic where Mary's pregnancy is a secret at first. She has to hide it from those who would oppose her having an heir. This could lead to all sorts of tense situations, like sneaking around to get proper medical care and advice without being detected.
Love and romance are common. Often, the OC will fall in love with Francis or be involved in a love triangle within the court. For example, in many stories, the OC might be a rival to Mary for Francis's affections.
A third plot idea might be that Francis and Vanellope get accidentally transported to a different genre of game. They are now in a medieval - style game instead of their usual racing or arcade - style games. They have to adapt to this new environment. Vanellope uses her quick - thinking and Francis uses his strength to find a way back home. During this time, they face knights, dragons, and solve puzzles.