Alex Logue's abused daughter, Astra (also called Astrid), had summoned up a demon called Norfulthing that had killed Logue and his associates during an orgy. John Constantine tried to summon another demon to defeat it but failed to name and bind it properly. That demon, Nergal, killed Norfulthing and dragged Astra to Hell. This failure sent John completely insane. He was committed to Ravenscar Secure Facility. The guilt stayed with him for a long time.
During the end of Critical Mass arc however, John succeeds in freeing Astra's and every child's soul trapped in Hell and held by the demon Buer. Astra kisses the (demon) John Constantine as thanks and she together with the other children quickly depart to Heaven.