The work of saving the world does not end even when you die

When Michelangelo dies opening the portal he expected to stay dead but is surprised by appearing in a new world where other turtles like them protect a version of New York from a wide range of enemies.
Trying to find meaning in a life without his siblings, he finds himself involved in the battles that these younger versions of his family have daily and his family dynamics.
When known energies begin to emerge and enemies from his past threaten this dimension, Mikey must join forces with the young turtles and his friends to prevent what happened to his world from being repeated in this one.
Maybe then I will find peace