First off

After becoming Vongola Decimo, Tsuna thought live couldn't get more crazier when Byakuran suddenly crashed his into Tsuna's office and screamed.

"Tsu-Chan! I'm sending you to another world for vacation!"

And that's when the drama starts
Tsuna finds himself in a parallel world where the First Generation is still alive and the worst part. His (parallel-parts) friends are Sons to the First Generation. But where is Tsuna's counterpart?
and to make matters even worst,

"Wait.....did..my counterpart die?!?"

LiveLifeER