A possible plot could be that their married life is disrupted by a mysterious force that is causing chaos in the magical world. Natsu and Lucy, being the strong couple they are, set out to find the source of this problem. As they journey, they discover secrets about their own powers and how their union might be the key to saving the world. There could be moments of doubt and fear, but their love for each other always pulls them through.
One possible plot could be that Natsu and Lucy go on a dangerous mission together. In the middle of it, they find a mysterious lemon - like magical item. As they study it, they start to feel a strange warmth between them. They then have to overcome their initial shyness and admit their feelings for each other while dealing with the power of this strange item.
Natsu and Lucy are the main characters. Natsu is known for his impulsive nature and great power, while Lucy is intelligent and resourceful. In a fanfic about their married life, their individual personalities would play a big role. For example, Natsu might be the one to rush into danger, while Lucy uses her wits to figure out solutions. And of course, their love for each other is what binds the story together.
Well, one possible plot could be that after many adventures together, Natsu finally realizes his deep love for Lucy. He might plan a big, romantic proposal during one of their guild parties. Then the wedding could be a grand affair with all their Fairy Tail friends in attendance. They could exchange heartfelt vows, and the whole guild could celebrate their union with lots of food, music and magic.
Maybe the story could start with Natsu and Lucy going on a special mission. During this mission, they face a great danger that makes them realize how much they mean to each other. Once they return, Natsu decides it's time to get married. The fanfiction could then focus on the wedding preparations, like Lucy choosing her dress and Natsu trying to find the perfect gift for her.
Perhaps the story delves into how they handle disagreements as a married couple. Since Natsu can be impulsive and Lucy is more level - headed at times, they might have to work through their differences. It could also show how their love for each other deepens through these experiences.
Well, perhaps Natsu could be sparring with Lucy and accidentally land a more powerful blow than he intended during a training session. Maybe he's in his dragon force mode and loses control for a second, hitting Lucy hard enough to make her fall and get injured.
Well, one possible plot could be that Natsu and Lucy's relationship evolves from friendship to something more romantic. Then, an unexpected pregnancy occurs which throws their lives into chaos. They might have to face the reactions of their friends and deal with their own fears and insecurities about becoming parents.
Typically, love and relationship development are common themes. Since it's about Natsu and Lucy getting married, there will be elements of how they adjust to married life. However, since 'lemon' might be involved, there could also be some more adult - themed relationship aspects like physical intimacy, but this is not suitable for all audiences.
One possible reason could be that Lucy is too focused on her own goals, like becoming a stronger mage or achieving something specific in the guild. She might see a romantic relationship as a distraction at that moment.
I'm not sure specifically as I haven't read this particular fanfiction. But generally, it might involve Natsu and Lucy having some sort of adventure or interaction at a lemon spa. Maybe they go there to relax after a tough mission and something unexpected occurs during their time at the spa.