Would this sort of idea be ripping off Tangled (Rapunzel)? Main character finds his parents dead. Blood everywhere. Main antagonist denies doing it and pretends to be good, offers to keep him safe. Eventually he realises he did it.
In a general sense it's ok if (coincidentally or not) you follow along those same lines. There's lots of stories that have that as a central plot device, that the person you trust is the one who really did the deed. As long as you have some unique and interesting stuff going on and the reader doesn't feel like they know where the story is going then it's not a problem. With good characters you can make it feel unique, a character reacting to this situation and eventual betrayal in a way that maybe we haven't seen before. Equally, written well the twist in the tail will still land well and appear suitably devious and interesting. Especially if you characterize that bad guy well you can take it some interesting places; look at why exactly they look after the kid, if they have changed over the years etc. To get a bit deeper on this; there's a reason why ideas aren't copywritten. Because if you think about it hard enough every idea has been done before by someone. The overall story are one part of what makes a story. The characters and the setting and the fine execution of each story beat matter perhaps more than the actual idea. There's infinite ways to tell the 'boy meets girl' love story and indeed every other story. It's the totality of the work that matters really, if the arcs and characters are following the same trajectory, if the setting is similar, the exact course of events. It an exercise I recommend to people who are struggling to come up with ideas that they feel confident about is to write their version of stories they already know and like; come up with everything else themselves just mirror a narrative that they already feel good about. Write your Star Wars or whatever just to keep yourself writing honing your skills and quickly they tend to quickly start coming up with new and interesting stuff off their own back. In my own work I don't really come up with 'ideas' as such, I just have a concept in my head of whose story I want to tell and then just tell it. So don't worry about it. If you're going to tell me there's a tower and the protagonist has to grow their hair then sure, maybe that's a bit much. But if you're doing anything else? Nah, no problems.
I think it's broad enough that it's OK. As long as it develops differently from that beginning point.
Don't worry about it. Both the novels I have on the go began life as rip-offs of books I had enjoyed, but as I kept writing them, they took off into something of their own. Most likely, you'll have an idea that takes the plot in a direction not even hinted at in Tangled/Rapunzel.
@Formalized 1) This is why I love TV Tropes so much: when you see something you like in a story, you can look for the story's TVTropes page, find the thing you like on the list of tropes that were used in the story, and then you can look at dozens if not hundreds of other stories that did the same thing in different ways 2) What does the choice of "A or B" refer to?
