One good plot twist could be that the main character, who has been searching for a missing heirloom throughout the story, discovers that it was in their possession all along, hidden in a place they never thought to look. Maybe it was inside an old family photo album that they never fully explored.
The main suspect in a mystery story has a perfect alibi that the detective can't break. But then it's discovered that the suspect has an identical twin that no one knew about. The twin was the one who committed the crime while the suspect was creating their alibi. This sudden revelation adds a whole new layer of complexity to the mystery and forces the detective to start their investigation anew.
One good plot twist could be that the character who seems to be the hero is actually the villain all along. For example, in a detective story, the detective who has been leading the investigation turns out to be the mastermind behind the crimes he's supposed to solve. It completely flips the reader's expectations.
'Nisekoi' is full of plot twists. Raku Ichijo is forced into a fake relationship with Chitoge Kirisaki to keep the peace between their rival gangs. But as the story progresses, there are so many twists and turns in their relationship. There are also other girls who may or may not be the girl with the key to Raku's locket, which was promised to his first love. It keeps you guessing all the time.
Plot twists in short stories are important as they add excitement. They can suddenly change the direction of the story, making it more engaging for the reader. For example, in 'The Gift of the Magi', the plot twist at the end shows the selfless love of the couple in a very unexpected way.
A great plot twist could be that the 'ghost' in the story is actually a person in disguise. For example, in a haunted mansion story, the main character thinks they're being haunted by a vengeful spirit, but in the end, it turns out to be the caretaker who's trying to scare people away to keep a secret treasure hidden in the house.
The motive for the murder was not what it seemed. Everyone thought it was about money or revenge, but it was actually to protect a secret that the victim knew. The murderer was part of a powerful organization, and the victim was going to expose their illegal activities. So, the murderer had to kill to keep the secret safe. This kind of plot twist makes the story more complex and interesting as it challenges the readers' initial assumptions.
One good plot twist could be that the person the main character thought was their soulmate turns out to be a long - lost relative. It completely changes the dynamic of the relationship and adds a whole new layer of complexity and drama. For example, they might have been on the verge of getting married when this revelation comes to light.