After the Justice League Dark's defeat and barely surviving in the attack on Darkseid's center, the Earth was nearly ruined and largely perished; Constantine devised a plan to have Flash enter his speedforce to create a Flash Point, then Constantine uses a spell to change the past, which means changing the present and future of the universe.
Constantine wakes up to find himself in a strange house, completely unaware of what happened and why he is in this house. He opens the door to a room and unexpectedly meets his close friends, his wife Zatanna Zatara and unexpected two children. After a few moments of initial happiness, all his beloved soon turn into demons and torment Constantine mercilessly. The torture repeats itself over and over, and Constantine lives in endless bloody cutting/splashing/beheading/tearing-apart, lasting for centuries.
Constantine manages to get out of the house and is stopped by Spectre. Spectre says that Constantine had upset the order of the universe and is being punished with eternal imprisonment in the House of Mystery. This can be understood that Constantine's plan to "Flash Point" and change the past after the Apokolips war was successful.
Constantine asks Spectre to publicly announce his sentence and Specter does so. However, this is a trick of Constantine so that the demons Constantine sold his soul to know his whereabouts and come to collect their "debt".
When the "creditor" demons appears, not one but three, Constantine used a trick to bind them in a magical circle and used their portal to escape from the house.
Out in space, Constantine meets Spectre again. Spectre further explains that the purpose of the House is to help Constantine live an eternal and happy life with the people he loves; But because of guilt feelings, or because he felt he did not deserve to have a happy ending, Constantine himself turned his loved ones into demons.
Spectre also states that the universe is actually a living thing, and that the House was a way to shield Constantine from the universe's revenge; However, now the window leading to the house is closed and the universe starts drawing Constantine into for restitution.
