Lost interest in my own fanfic

I'm trying to finish writing a one-shot. It's a simple plot. But now I've hit writer's block because, suddenly, the story feels boring to me, and I don't know what should happen next. I feel like the issue might be that I don't fully understand the characters I'm writing, and I may need to revisit the canon material and study how these characters think. But I really wanted to finish this story before my vacation ends. What do you suggest I do? How do you avoid getting bored with your own fanfic?
The plot, if anyone is interested, is that a character from the original series experiences memory loss, and the rest of the cast has to figure out a way to restore their memories and deal with them—because the old version of this character is evil. I've managed to reach the part where they lose their memory, and now the characters are trying to come up with a plan to solve the problem while the problematic character escapes, causing chaos and trying to understand this new world where everything is different from what they remember due to the passage of time. But now i don't know what sould happen next!