Perhaps Merlin has to save the knights from a curse. He could go on a long journey to find the ingredients for an antidote while facing many obstacles along the way. He might have to outwit evil spirits or solve difficult riddles to get what he needs to break the curse on the knights.
In some fanfictions, Merlin could save the knights from a political conspiracy. The knights are framed for a crime they didn't commit, and Merlin uses his magic and his wits to expose the real culprits. He might use his ability to communicate with animals to gather evidence, or magically create illusions to deceive the conspirators into revealing their true motives.
One interesting plotline could be the knights and Arthur facing a new, powerful dark magic threat that only Merlin's unique powers can help them overcome. They might journey to a far - off land in search of a magical artifact Merlin has foreseen as the key to victory.
Well, obviously Merlin is one of the main characters. He is the one with the magic and the power to save the knights. The knights themselves are also main characters, like Arthur, Lancelot, Gwaine etc. They are the ones in need of saving and are often the ones getting into dangerous situations that Merlin has to rescue them from.
A plot could involve Merlin getting cursed and the knights having to find a way to break it without Merlin's magic to guide them. They might have to rely on old legends and their own wits to save him. This could lead to some great character development for the knights as they face challenges they usually rely on Merlin to solve.
Another plotline might involve Merlin coming back to find Camelot in chaos. His return then becomes a journey of restoring order, not just through his magic but also by reuniting the people and rebuilding their trust in the kingdom. He might have to deal with those who have misused power in his absence.
Maybe a plot where Arthur and the knights get a glimpse into Merlin's past through some magical artifact. They see his early days of learning magic and the struggles he faced, which makes them understand his motives and loyalty better. This could lead to a stronger bond between them all.
One possible plotline could be Damon using his vampire abilities in a unique way to rescue Bella from a dangerous situation, like a group of rogue vampires. Maybe he uses his speed and strength to fight them off.
Another interesting plotline could be related to the prophecy or some sort of hidden danger that only Shanks is aware of. He saves Luffy not just from an immediate threat but from a long - term danger that could have ended Luffy's journey towards becoming the Pirate King. Shanks might have to sacrifice something of his own in the process, like his position or a precious item, to ensure Luffy's safety.
One interesting plotline could be Hermione using her vast knowledge of magic to outwit a powerful dark wizard who has everyone else under a spell. She might find a long - forgotten spell in the library that can reverse the dark magic.
One interesting plotline could be Snape's internal struggle as he tries to save the Potters. He has complex feelings towards James Potter, yet his love for Lily drives him to protect the family. Maybe he has to outwit Voldemort's inner circle without revealing his true intentions.
One interesting plotline could be Naruto having to team up with unexpected allies from different villages to save the world. Maybe he has to work with some of the old villains who have a change of heart due to a greater threat.