Ever since Agents of Shield decided not to address that big purple, hunky titan Thanos arriving on Earth and wiping out half the universe, we've had questions. Why weren't Coulson and the gang turned to dust? Now, we seemingly have an answer.
During the episode "Brand New Day", it becomes clear that Agents of Shield plays by the same time-travel logic presented in Avengers: Endgame (opens in new tab). In short, when things change in the past, it doesn't mean the future will change, but instead, an alternate timeline gets created. That's why, when Captain America and the gang steal the Infinity Stones from the past, their future is not altered.
It's also why Cap travels back to return the Infinity Stones at the end: so those timelines aren't altered. Why does Cap appear in the main timeline at the end was a big question we had, but the Russo brothers explained that away by saying Cap actually uses a Pym Suit to return to the OG timeline while off-screen. Sure.
Back to Agents of Shield. We see the same logic play out when Mac's parents are killed – Mac doesn't blip out of existence despite never being born in that timeline. That event led to some confusion among the agents.
"They didn't deserve to die, but it's also the proof you needed," Daisy's sister Kora – who died in the original timeline but remains alive here – tells the team.
"Proof that this is a new timeline," Coulson replies, having realised the inevitable truth. Yet, it's when the episode ends that things become irreversible on this timeline.
The alien invaders the Chronicoms manage to take out every Shield base going, including the Triskelion, seen in Captain America: The Winter Soldier. The extent of the destruction is shocking.
The big question now is: can the agents save the day on this timeline? And if they do manage to salvage the situation, will there be an original timeline to go back to? The team has literally nothing to lose and seeing them fight the Chronicoms come the series finale should be a breathtaking closer. Let's just hope they can find their way home once they have saved the day. And if you're still wondering where Agents of Shielf fits into the Marvel timeline? We have you covered.