The Amazing Spider-Man, Vol.2 #535

The Civil War is leaving Peter Parker with many sleepless nights, and when he hears that Stark Enterprises and Fantastic Four Inc. have been awarded huge no-bid contracts for a superhuman detention facility, he begins to wonder about Tony's motives. Confronting him about it, Peter asks to see the prison that's been constructed in the Negative Zone.While the prison is hardly inhumane, Peter isn't happy with the fact that the prisoners are kept in a legal and literal limbo, without any access to the judicial system or due process. They are exiled to this prison until they register with no trial, or other opportunity for release.After having seen this, Peter comes to the realization that he's on the wrong side of the war. But how long will he have to get Aunt May and Mary Jane away from Tony before he realizes what Peter is up to?