As the fourth season begins, "In Aloha kekahi i kekahi", NLM terrorists attempt to kill Wo Fat but McGarrett saves him. Before Wo Fat is transferred to a Supermax facility in Colorado, McGarrett wants an answer from Wo Fat why Doris visited him. Fat says she wanted to apologize to him for killing his father. In "O ka Pili'Ohana ka 'Oi", he is given medication in his solitary confinement cell by an officer for his heart condition. He is asked to swallow the medication and open his mouth so that it is certain he ingested it. Wo Fat hides the pills well in his mouth and reaches inside his toilet to reveal that this is not the first time he has faked it. He then uses the medication along with paint thinner and fertilizer from the jail, to craft an explosion to take out a wall in his cell to escape. He is positively ID'd at a gas station near Colorado Springs, pouring gasoline on someone, lighting them on fire, then stealing their truck to head back to Oahu. After Grover's daughter Samantha is freed from Ian Wright's capture, she tells everyone that a man, revealed to be Wo Fat, killed Ian and released her. McGarrett is given a message from Samantha that Wo Fat will see him soon.