One possible plot could be that Spencer and Marco team up to solve a new mystery in Rosewood. Maybe there's a series of strange events that the police are overlooking, and Spencer's sharp mind combined with Marco's detective skills make them an unbeatable duo.
A plot could involve Spencer getting into some trouble that only Marco can help her out of. For example, she might be wrongly accused of something at school or in the community. Marco, believing in her innocence, uses his resources to clear her name while they also develop a deeper connection along the way.
Perhaps a fanfiction could revolve around Spencer and Marco going on a road trip together for some reason. During the trip, they encounter various obstacles and have to rely on each other. This could lead to them sharing secrets, having heart - to - heart conversations, and ultimately falling in love.
The parents could also be important characters. Spencer's parents might have concerns about her spending time with a detective, while Marco's family background could be explored. Maybe his parents were also involved in some mystery - solving in their youth, which influenced him.
A great plot could be that Spencer gets into some trouble with her studies and her family's high expectations. Wren, being the older and more experienced one, offers to tutor her but in a very unorthodox way. As they spend more time together, they start to realize their feelings for each other are deeper than they thought. And this relationship development could be intertwined with the mystery and danger that always lurks in Rosewood in the Pretty Little Liars setting.
A really interesting plot could be set in an alternate universe where Toby is a detective and Spencer is a journalist. They team up to investigate a series of strange disappearances in their town. As they dig deeper, they start to realize that there are forces at work that are much bigger than they initially thought. Their relationship evolves from professional partners to something more romantic as they face danger together.
One idea could be Spencer dealing with the shock of the pregnancy while trying to keep it a secret from her friends. She might be worried about how it will affect her academic future and her relationships within the group.
One interesting plot idea could be that Spencer and Aria have to team up to solve a mystery that's related to their pasts in Rosewood. Maybe it has something to do with a long - forgotten event from their childhood that starts to resurface in strange ways. For example, they could start receiving anonymous letters that hint at a secret they buried long ago. Another idea is that they find out they have a hidden connection to one of the 'A' threats. They might discover that they unknowingly have some power or knowledge that 'A' wants, and they have to use their wits and friendship to outsmart 'A' and keep themselves and their friends safe.
There are many great writers out there. Some popular ones are often those who are really good at capturing the personalities of Spencer and Toby as they were in the show. For example, some writers on fanfiction.net have a large following for their PLL fanfics. But it's really subjective, as different people like different writing styles.
Another aspect in fanfiction could be a romantic relationship between them. Their personalities, which are both strong and independent, can create a very passionate and intense dynamic. Writers might explore how they deal with their feelings in a world full of secrets like in Pretty Little Liars.
One common theme is mystery. Since the show itself is full of mystery, fanfictions often continue this trend. Spencer and Alex might be involved in solving a new mystery together, perhaps related to their families or the town's secrets.
I'm not sure who the 'best' is as it's subjective, but some popular authors might be those who have a large following on fanfiction platforms. Look for ones with high ratings and lots of reviews. For example, there could be an author named 'RoseWriter' who is known for her detailed characterizations of Emily and Spencer.
One key element is the character interaction. How Spencer, with her intelligence and complex personality, interacts with Dean, who likely has his own set of skills and traits. Another is the setting integration. Incorporating the dark and mysterious world of Pretty Little Liars with Dean's possible role in it. Maybe he could be helping to uncover the 'A' mystery or dealing with the other secrets in Rosewood.