The Multiverse of Loss (A TMNT 2012/ROTTMNT Crossover Fic)

When the Rise of the TMNT turtles lose their Leonardo on the way through a portal, they wind up stuck in an alternate dimension with Leo's mystic portal-generating ōdachi sword. They must come together to work with the alternate versions of themselves and put the loss of their brother behind them, especially considering they don't know if he is gone forever.

Meanwhile, the 2012 turtles are still trying to cope with the loss of their father.

What happens when these two devastated groups of mutant turtles have to rise up and work together to overcome all sorts of challenges?