Thor has been King for a few weeks now. All the focus is being put on the wedding between Y/N and Thor. Loki knew he needed to complete his plan before Thor gets married. He knows it is treason to do what he is planning, but he plans on making it look like an accident. Over these few weeks, he finished getting everything together and he is finally ready to execute his plan and get Thor out of the way.
While Odin, Frigga, Y/N, and Thor are busy with wedding planning, Loki goes to the Bifrost. He makes sure Heimdall is taking care of first. He freezes his whole body with The Casket of Ancient Winters and gets him out of the way. Next, he prepares the Bifrost for what is about to happen. Loki is going to send Thor to Jotunheim. He has a deal with the frost giants. If they kill Thor, he will give them the Casket.
Thor and Y/N have been spending a lot of time together planning the wedding and their future but not really getting to know each other. Y/N is accepting that she won't really know Thor the way she wants to before the wedding takes place. Frigga has been spending the most time with Y/N preparing her to be Queen. Everything is going perfectly. Odin and Frigga are very happy with how everything is going. The date of the wedding has been decided.
Thor: that date is perfect.
Frigga: I'm so happy for you both.
Frigga hugs Thor. Thor and Y/N both see light out the window from where they are in the castle. As the King of Asgard, he should be notified of anything happening with the Bifrost. Y/N just ignores the light but Thor knows something is wrong. As King he needs to check it out. He flies with his hammer, Mjolnir, to the Bifrost where he sees Loki.
Loki: This is for you Brother.
Thor: Loki, this is madness.
Loki: Is it madness? Is it? Is it?
Thor doesn't know what to do. He doesn't want to fight his Brother. What did he do to Loki? But Thor can tell Loki messed with the Bifrost and Loki said it was for Thor. Where does his brother want to send him?
Loki: Once you're gone, I can be happy again finally.
And just like that Loki sprung towards Thor. Loki needs to get Thor in the proper place to send him to Jotunheim. Loki kicks his brother down and swings around to kick him again before he gets up and starts fighting back. Thor gets up as fast as he can though. He doesn't want to fight Loki, but he will.
Thor grabs Loki and throws him. He love Loki and he can't believe Loki is doing this. Especially now that Thor is King. Thor jumps towards Loki. Loki turns around quickly and uses his magic to stop Thor from coming towards him. But Thor flew right into Loki and his magic hit a part of the Bifrost which caused it to explode. Thor and Loki got caught in the explosion and were thrown onto the rainbow bridge.
Loki looks up after being flung and sees Thor using Mjolnir to destroy part of the rainbow bridge and the Bifrost. Thor acted quickly. Part of the Bifrost exploded and Thor knew he needed to just get rid of the Bifrost all-together. Loki could still send him somewhere which he couldn't let happen. He must destroy the Bifrost.
Loki: What are you doing?
Thor continues to hit the rainbow bridge. Loki needs to stop him. All he feels is rage. His plan is going to waste. In that moment, Loki gets up and Loki jumps towards Thor. At this point, he'll kill Thor himself. As Loki jumps, Thor destroys the bridge. Thor destroying the rainbow bridge created a huge explosion because it also destroyed the Bifrost completely. Loki and Thor flew up into the air.
