One common theme could be mystery. Since 'light gets caught' might imply something unexpected or strange happening with light, it could lead to a mystery - like what caused the light to be caught and what are the consequences. Another theme might be transformation. The event of the light getting caught could potentially change a character or a situation in some way.
I haven't come across much 'light gets caught' fanfiction myself. But you might want to check out relevant fan communities on social media platforms. They often share and discuss interesting fanfics in this area. Maybe someone there can point you to some great ones.
"The Man Captured by Light" had a rating of 7.0 on Douban. This movie was directed by Dong Runnian and starred Huang Bo, Wang Luodan, Tan Zhuo, and Bai Ke. The story described a mysterious white light that descended on Earth and captured some people. This phenomenon attracted the attention of scientists and the media. The movie was linked by four clues, showing the love stories of different people. Although Douban's rating was 7.0, the film had a good reputation after it was released in the New Year's period. Cat's Eye had the most people who wanted to watch it. The film filled the gap in the genre of realistic light sci-fi films.
In some fanfictions, Dumbledore is portrayed as having a lot of secrets. If he gets caught, it could be related to his past. Maybe some old enemies find out where he is and catch him. Then he would have to deal with his past coming back to haunt him. His friends might try to rescue him, but it would be a very difficult situation for him, and it could change the whole dynamic of the fanfiction story.
One possibility is that Dumbledore gets caught spying on a group of Death Eaters. This would put him in a very dangerous situation as the Death Eaters are extremely cruel and loyal to Voldemort. He might be tortured for information about the Order of the Phoenix. However, Dumbledore is very resourceful and would probably be able to hold his own against them for a while, giving his allies time to figure out a rescue plan.
There was a mom who got caught trying to spy on her teen's text messages. She took the teen's phone while they were sleeping, but the teen had set up a camera in their room to catch any intruders (as a joke). So, when the teen checked the camera footage later, there was the mom looking through the phone.
Since I haven't actually read this particular fanfiction, it's hard to say for certain. However, based on the title, we can assume that Richie is the main focus. The Deadlights are likely some sort of supernatural or dangerous element. It could involve Richie being trapped in a world created by the Deadlights, facing his worst nightmares perhaps, and the story might be about his journey to break free from this terrifying situation, whether through his own strength or with the help of others.
It's completely inappropriate. In a civilized society, we should respect the boundaries of others' privacy. A story like this involves a very private and potentially shameful situation for the girl. No one should be made the subject of such a story being spread around, as it goes against basic principles of respect and decency.
If it's a family member who catches her, they should approach the situation with empathy and understanding. Let her know that it's a normal part of growing up and that she has the right to privacy. Avoid shaming or scolding her.