The explosion of the beacon trapped by General Hale results in the destruction of Noah and three obelisks, ripping a hole in space-time to another dimension.
This causes the teams' fears to manifest in the Lighthouse in a very physical way, as they discover when a Kree warrior attacks Daisy and Deke.
Fitz quickly comes up with a potential solution (or at least a temporary stopgap measure), but it might require one of the team to sacrifice themselves to deliver the device to the rift.
Chaos erupts when Coulson immediately volunteers himself. After he passes out briefly, it's finally revealed that he's dying, and he's been so for awhile, ever since he was possessed by the Ghost Rider.
He takes the device, only to encounter a specter of Mike Peterson, who tells him that everything he's experienced over the past few years has been an illusion, that he's still on the table after being stabbed by Loki.
After Coulson rejects the claim, the illusory Peterson attacks him. Fortunately, the real Mike shows up, having been summoned by Deke. Together, Coulson and Mike fight off the fears and successfully close the rift.
Later, Fitz and Simmons finally get married in front of all their friends, and General Hale simultaneously learns some shocking news: Deke is, in fact, the grandson of Fitz and Simmons.