The accident.

Donnie, in all his genius glory, isn't perfect. His tech isn't perfect. And God knows his experiments aren't perfect. And that's never bothered him much, until one day his experiments mishap causes a mistake that could have deadly consequences for everyone's favorite blue masked turtle. Can he save his beloved twin, or will Donnie have to live with the guilt of what he's done for the rest of his life.
{My friend came up with this and I loved it sm so fic time~}