How to Escape from a Superpowered Women's Prison

"How does it feel to be locked up somewhere full of girls?"

"You should ask me what it's like to be locked up with a pack of adorable-looking monsters."

Hill gets himself sent to the prison known as "The Grave," where superpowered criminals are held, and waits for a chance to escape. But even if he can get out of a prison made of iron, can he escape the prison made by people?