When Mikey gets a trigger that leads him to have memories of his life as a turtle pre mutation, he learns things he wishes he didn't about a certain someone, how will he cope and make sense of his past and how will his family react?
(Inspired by the stories where 12!Mikey and Rise!Mikey switch)
After the invasion and discovering his new powers Michelangelo starts training to get better at it. His powers seem to have a mind if it's own and it's worse when he sleeps. He doesn't want something terrible to happen, so he trains from sunrise to sunset.
On one particular night when everything seems to be going wrong Mikey lashes out and accidentally sends himself to another world. His powers are on the fritz and he can't use them without his arms feeling like their on fire. All he can do is wait and hope his brothers can make due with their new guest.
(Rise! universe is after the movie.)
(2012! is like at the end of season 3 or the beginning of season 4, basically it's after the space arc)