Stark had an event he needed to appear at. He had extended an invitation to the others. Thor wasn't going anywhere in his state. But after some pushing from him, they all agreed to go. They had all been coped up inside with him all month and they deserved a night out.
He then promised he would be fine and he would call if he needed anything. He was fine at first, but Loki could see him mind wandering with the lack of people to distract him. Wandering into dangerous territory.
It wasn't too long before he ended up in his room, on the verge of tears. Needing someone, but not knowing who. Loki did. He though it over for a while. It was the sheer pain in his brother's eyes that made up his mind. So he revealed himself.
At first he wasn't noticed. Loki knew that is was only a matter of time before Thor noticed his presence. And he was right. Only a couple minutes passed before Thor slowly looked up. Not knowing who would be there but certainly not expecting Loki.
First it was disbelief, the next was denial. Then acceptance and finally, anger mixed with happiness. He was just staring at Loki, not knowing whether to hug him or kill him. Loki just stood there. Waiting for him to do something. Waiting for some sort of reaction from him.
When nothing came he took a hesitant step forward. He hesitated a second time before speaking. "I know you're angry. I know you're upset. I know I have a lot to explain. And yes, I was planning on keeping this from you. For my own reasons. But you're right, we are brothers. I hate you, but I love you. So I can't just sit by and watch you suffer through this alone. So here I am."
He goes silent, waiting for Thor to say something, anything. Instead he gets up off the bed and walks over to Loki, standing right in front of him. He stands a minute before smirking, one of the unshed tears falling down his face. "I missed you." He barely whispers it before reaching out and embracing Loki. And for the first time in years, Loki hugs back.
