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 Lucy, but Eli, who already was obsessed with completing the machine, finished it and put himself into the contraption. When the machine activated, the shockwave hit Coulson, Fitz and Reyes, within the radius and shifted them into another dimension, while allowing Morrow to have the ability to create matter.
Sinking into Hell
The longer that they were in the dimension, they 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, followed him and made a new deal with the Spirit that if it helps him stop Eli, he will settle all its scores. the spirit accepted and merged with Reyes again.
The Rescue Plan
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 and Leo 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.
Later, Robbie Reyes, accompanied the Spirit of Vengeance, used the gate to return to Earth as well.
The Inter-Dimensional Gate would later be used in the Battle at Chinatown Crew Headquarters to stop Eli Morrow. By reading the Darkhold, both 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 LMDs.