In a Wattpad story, the 'one big mistake' could be related to a misunderstanding. Let's say the main character misinterprets the intentions of another key character. Maybe there are some hidden signals or clues that the character fails to pick up on, and as a result, they make a move that has far - reaching consequences for the whole story. This could involve starting a feud with someone who was actually trying to help them, or leaving a place where they were actually safe.
Well, without actually reading the specific Wattpad story, it's hard to say exactly what the 'one big mistake' is. It could be a character's decision like choosing the wrong path in a love triangle, or perhaps making a bad career choice that sets off a chain of negative events in the plot.
The 'one big mistake' in the Wattpad story might refer to a moral error committed by a character. For example, if it's a story about a group of friends, one of them might lie about something really important, which then leads to a rift among the group and all kinds of problems. It could also be a strategic mistake in a fantasy adventure story, like a hero going into a battle unprepared because of overconfidence.