One last chance
Loki is an important character in the Avengers movies. He is one of the famous Norse gods, one of the princes of the planet Asgard, brother of Thor and son of Odin. In the first movie, he landed on Earth with a Chitauri army to try to take over. But he was stopped by the Avengers and brought back to Asgard by Thor. In Avengers Endgame, the Avengers decide to travel back in time to try to gather the Infinity Stones before Thanos can gather them. They find themselves at the time and place where Loki had just been arrested. In the confusion, the Tesseract falls out of a briefcase and Loki manages to retrieve it to teleport away from the Avengers, creating, unbeknownst to us at the time, a new timeline.