The truth
Landon paced around his room trying to piece everything together. He already had most of the facts and the only thing missing was the key.
To get that he knew that he needed to put aside everything and use his heart. Arian's conversation with the masked man gave him key details of what was going on.
He was stuck in a never ending loop of prisons and has been for a thousand years. For some reason Arian hated him for something he must have done. Something that he doesn't recall just as he doesn't remember all the things that happened.
He looked to the bed where Arian laid. The man looked broken and damaged when the masked man left. He broke down and completely shattered. He knew the feeling too well.
He felt it a lot when he and Theo had to part ways when Lysander was taking revenge on him. When he was left with no road left in his life. Losing his past, present and future.