Takes place after 'Mutagen Man Unleashed'
Donatello is still upset about what happened with April O'Neil's father and blames himself for what had happened. One night when he went to get some fresh air he saves a purple haired girl named Rarity and her sister Sweetie Belle who were attacked by Purple Dragons. They become friends and Donatello begins to fall in love with Rarity. But a part of his heart still tells him that he loves April and now he doesn't who to choose. April the one who he's known for what felt like so long. Or Rarity the one who was there for him to help fix his broken heart.
Credit goes to @kiana1506 because she's the one who gave me the idea