Chapaev and Void

The hero of the novel is a decadent poet, a Red commissioner, and a patient in a psychiatric hospital, Pyotr Void. Every time he falls asleep in the division of his commander Vasily Chapaev, he wakes up in an asylum for the insane. Pyotr is convinced that the asylum is a product of his imagination. However, Chapaev assures that both of these worlds are unreal and Pyotr just needs to finally wake up. But how to do it, if instead of reality, there is a shining void?