Loki kicks off by taking us back to 2012 and the events of The Avengers, moments after the God of Mischief was captured by Earth's Mightiest Heroes. From there, we once again see Tony Stark and Ant-Man bungle their theft of the Tesseract, and the villain is able to make his escape. After a rough landing in the Gobi Desert, it takes almost no time at all for the Time Variance Authority to show up, apprehending Loki with ease before taking him into custody. No one seems particularly phased by him - or the Tesseract - at the TVA, and after a series of humiliating ordeals that see the trickster forced to verify everything he's ever said and get fitted with a prison jumpsuit in place of his Asgardian gear, the organisation is explained to Loki courtesy of Miss Minutes.
She says there was once a Multiversal war that saw countless unique timelines battle for supremacy. However, the "all-knowing" Time-Keepers then emerged to create a single, sacred timeline, and it's up to the TVA to protect the proper flow of time. If a "Variant" steps off the path, a Nexus event is created that, if left unchecked, could lead to another Multiversal war. The TVA - created by the Time-Keepers - set things right by destroying those timelines, and in 1549, we see that play out when Mobius investigates the murder of some agents and the theft of one of the reset charges that wipe away these branches. A young boy points to a picture of the devil and says he was responsible for what happened there while also showing Mobius a candy bar wrapper that definitely didn't come from this time period.
Loki, meanwhile, is put on trial and found guilty. His powers are useless in the TVA, and he's sentenced to be "reset." Mobius requests access to the God of Mischief, and after witnessing the scale of the organization, it's clear Loki is humbled somewhat. A lengthy interrogation follows that sees Loki learn more about how the TVA works as Mobius takes a deep dive into whether the villain really is as bad as he seems. During this, we learn that Loki was actually D.B. Cooper and came to Earth after losing a bet to Thor. Loki is also given a glimpse into his future and the role he played in his mother's death. It clearly has an impact on him - just as it did in Thor: The Dark World - and when Mobius leaves the room with Hunter B-15, the villain manages to escape using a piece of tech that returns a person to where they last were in time. After retrieving the Tesseract, Loki finds a whole drawer of Infinity Stones and learns that they're used as paperweights in the TVA. It's at this moment he seems to realise how powerful this group really is.
Returning to that interrogation room, Loki witnesses his future, including the way his relationship with Thor improved, Odin's demise, and his own death at the hands of Thanos. Outsmarting Hunter B-15, Loki removes the collar stopping him from using his powers, but is still there when Mobius returns. He tried using the now powerless Tesseract, but realises he can't go back to his timeline. Admitting that he doesn't enjoy hurting people, Loki says he's only ever done that because it's part of the illusion of who he is; a cruel, elaborate trick created by the weak to inspire fear. Mobius doesn't view him as a villain, though, and wants his help catching a variant. Why? That variant is Loki!
In 1858, the TVA respond to a disturbance in the timeline, but end up being murdered by this hooded Loki variant, and that's where we're forced to leave things until next Wednesday...