Another plot could involve their relationship being tested by external threats. Like a meta - human villain who discovers their secret and tries to use it against them. They would then have to decide whether to come clean to their friends for help or try to handle it on their own while still protecting their relationship.
A great plot for a Barry and Caitlin fanfic could be a parallel universe story. In this universe, Barry and Caitlin are the only ones who remember their original reality. They have to work together to find a way back home while also dealing with the different versions of their friends in this new universe. This would be full of drama and also a chance for their relationship to grow.
Some fanfics might have them bonding over their shared experiences with their powers and the traumas they've faced. This shared understanding could lead to a deeper emotional connection that eventually turns into a secret relationship. For instance, Barry might confide in Caitlin about his fears of losing control as the Flash, and Caitlin can relate with her experiences related to her work on meta - humans. This could be the start of their relationship development.
A great plot could be that an old enemy of The Flash targets Caitlin to get to Barry. Barry then has to protect her at all costs. During this time, they go into hiding together. In the process of hiding and fending off the enemy, they discover things about each other that they never knew before. This shared experience strengthens their bond and leads to a new chapter in their relationship.
There is a fanfic called 'Caitlin's Discovery about Barry'. In this, Caitlin uncovers a hidden side of Barry that no one else knew. It's a great exploration of their characters. You can also check out 'Barry and Caitlin: A New Beginning' which gives a fresh take on their relationship, starting from a different point in the story.
One idea could be a time - travel plot where Barry accidentally takes Caitlin and Jesse to a different era. There, they have to work together to find a way back while also facing the challenges of that time period, like dealing with different versions of their friends or foes.
A plot could revolve around Caitlin and Barry being forced to work undercover as a couple to infiltrate a criminal organization. As they pretend to be in love, they start to realize their true feelings for each other. Or perhaps Caitlin's scientific knowledge and Barry's speed are the only things that can stop a city - wide disaster caused by a malfunctioning S.T.A.R. Labs experiment.
One common theme is friendship. Many fanfics explore how Caitlin and Barry's friendship develops over time, especially considering their different personalities and abilities. Their friendship is often a source of strength for both of them.
Often, it starts with friendship. They work together as part of a team, so they get to know each other's personalities. They might start by having simple conversations during breaks between missions or experiments. Then, as they spend more time together, they begin to notice little things about each other, like Barry noticing how Caitlin is always so dedicated in her scientific research, and Caitlin seeing Barry's kind heart beneath his superhero exterior.
One interesting storyline could be Barry and Caitlin going on a parallel universe adventure together. They might discover new powers or face off against versions of themselves. Another could be a time - travel plot where they have to fix something in the past that affects their relationship in the present.
Well, Dr. Wells could be an important character. He might have some knowledge or secrets that are relevant to the story of Barry and Caitlin. His presence could add a sense of mystery and also some conflict. Another option is Killer Frost. If Caitlin is struggling with her alter - ego, it could be a major plot point and Killer Frost could interact with Barry in unique ways.