What would have happened if the Shiroyasha never existed?

Edo is thrown to chaos by a mysterious cause. Sakata Gintoki, now lives in a world where the future has changed, without him. What has happened to the Yorozuya?

Gintoki, who is now a ghost of the past, must once again carry the burden in order to save his friends. He must finish the biggest job ever, which may be the final job of Yorozuya.

[Source: MAL]