Plot summary
Mace and Coulson infiltrate a Hydra "Enlightenment Camp" to free an undercover agent— Antoine Triplett, a S.H.I.E.L.D. agent who died in the real world. They are tracked there by May, who uses a super serum to fight Mace. Through the vents in their holding cells, Daisy learns from Radcliffe of a backdoor he installed to escape the Framework that Aida is unable to disable. Coulson attempts to save one of his former students who he sees being held in the camp; Mace follows him into a building to help.
Hydra uses a missile to bring the building down and May enters the rubble to ensure Mace is dead. She finds him stopping debris from crushing the student, with Coulson and Triplett helping other children escape the building. May is horrified to find children being victimized by Hydra. With the others having escaped to safety, Mace is crushed beneath the debris and, in the real world, Aida finds his physical body dead, as well. Turning on Hydra, May sneaks a Terrigen crystal to Daisy so she can regain her Inhuman abilities within the Framework.
Credits
Adapted from Wikipedia contributors, Agents of S.H.I.E.L.D. season 4. HTML formatting and reference markers removed.