Searching for a gigantic, blood-thirsty mutant bat is hard work. Creating an antidote for said bat was even harder, especially with three impatient brothers and indignant best friend- Donatello would know. With little time and motivation left, Donnie finds himself plagued with guilt over not being able to cure April's father. In an attempt to fix what he had broken, the genius inadvertently puts himself in harms way. Who knew one simple, solo mission could change so many things? An AU. I've watched the 2003 episode of TMNT, 'Good Genes' a million times just so I could write this story. I love the episode and I'm committed. Love you all!!! <3