The S.H.I.E.L.D. team went to stop Lucy Bauer from activating a machine that could cause catastrophic damage in her attempt to become corporeal again. They were also there to attempt to save Eli Morrow, who was taken prisoner by her to complete the machine. Ghost Rider was able to kill Bauer, but Morrow, who already was obsessed with completing the machine, finished it and put himself into the contraption. When the machine activated, the shockwave hit Phil Coulson, Leo Fitz, and Reyes, making their bodies out of phase with the Earth realm, effectively leaving them stranded between two dimensions, while allowing Morrow to have the ability to create matter.
Sinking into Hell
The longer they were out of phase with the Earth realm, the three started to feel the pull of another dimension trying to bring them further from their own. The Spirit of Vengeance also felt the pull from its home dimension and desperate to avoid returning there, it abandoned Robbie Reyes and took possession of Alphonso Mackenzie. Reyes, riding with Daisy Johnson, followed him and made a new deal with the Spirit that if it helps him stop Eli Morrow, he will settle all its scores. The spirit accepted and merged with Reyes again.
Unable to find other options, Melinda May insisted that they us the Darkhold to bring back her teammates. She showed the book to Holden Radcliffe but after a quick glance, he closed it, saying the information was too much for the human mind to process. Wit some help from Fitz, Aida suggested she should loo at the book. It was revealed to May and Coulson that Aida was an Life-Model Decoy so she might be able to handle the information. She read the book and found the solution to save them.
The Way Out
Making the Laser-Coupling Gloves, Aida made the Inter-Dimensional Gate. As a portal was formed, Phil Coulson and Leo Fitz were struggling to reach it as they fought against the pull of Hell. But they were able to push through and made it back to their own dimension.
The Inter-Dimensional Gate would later be used in the Battle at the Chinatown Crew Headquarters to stop Eli Morrow. By reading the Darkhold, both Holden Radcliffe and Aida suffered from corruption, and planned to use it to fulfill their desires and gave them the means to make a perfect brain for Life-Model Decoy.