Bring Me To Life

John turns to the dreamshare technology during the Hiatus, in order to be with 'Sherlock'. When Sherlock returns, he finds that John has chosen to drop into limbo to be with Sherlock's projection permanently. Sherlock decides that even if its the last thing he'll ever do, he will wake John up to reality.
Crossover with Inception. Only the verse borrowed. A reader doesn't need to have seen Inception to enjoy the story.

(OP which inspired the story: "When I appear it's not so clear if I'm a simple spirit or I'm flesh and blood.")