Cyrus learned that the police were investigating him for the murder. Tom called him and said that he was the one in power now. 

In flashbacks, the pair met up and Cyrus manipulated him into attacking Jenny. When Vargas figured it out, he went crazy at Cyrus. 

He told Cyrus he would make sure he would rot in jail. 

In another flashback, Tom said he would get rid of Vargas to make Cyrus president. He was shocked, but you could tell he was entertaining the idea of becoming the president. 

Abby tried to tell Fitz that Cyrus was probably not the killer, but Fitz was having none of it. He offered Cyrus a deal to get off with it. 

The deal would involve Mellie winning, so Cyrus was against it. 

Eventually, Cyrus came clean to Michael and decided to sort things out. In the end, he tried to kill Tom, but Tom got the upper hand.

In the end, Tom decided Cyrus would have a fate worse than death and would rot in jail. Tom then admitted to the murder of the president and said Cyrus paid him. 

Cyrus was arrested and Mellie got the news that she was going to be president.