Elderly mystery writer Millicent Shand (Mildred Natwick) visits the Cryogenic Institute run by Dr. Kirk (Peter Lawford). She says that she is interested in seeing if she would like to retire there and be frozen after death. Actually, she hopes to gather evidence that her late friend was murdered so the Institute could collect a $2 million bequest she left to them in her will.
Convinced that she is right, Millicent visits the Governor and urges an investigation. When McGarrett makes little progress, Millicent plays detective. She checks into the Institute and signs papers leaving all her future royalties to it. Having falsely reported that she has a bad heart, she expects that the physical they give her will confirm that. She is surprised when Dr. Kirk tells her that her heart is fine. Can this place be on the up and up after all? Then she gets a call from one of the doctor's aides. He says that other tests have revealed that she has an incurable brain tumor. When she reports this to McGarrett, he gets the tests redone by another lab. To his surprise, these tests produce a similar result. Millicent is dying from a brain tumor.
Returning to the Institute, Millicent tells Dr. Kirk that she will go to the mainland for treatment. He suggests that she postpone her departure for a day or two so that she can witness the revival of a man who has been frozen for six years. She agrees but lets McGarrett know of her change in plans. He arranges for Danny and Duke to pose as power company employees so that they can spy on the thawing. What they see impresses them profoundly. But McGarrett says, "You're out of your gourds!" He's positive that it's a con.
Millicent was impressed, too, but wants to check out her theory. So she sneaks into the room occupied by the man who was revived, James Royce (Fred Ball). Although he is evasive, she manages to get him talking about her books. Inadvertently, he mentions one of her latest ones. Now she knows that she is in mortal danger and begins a hide-and-seek game with Kirk and his attendants.
Meanwhile, McGarrett has returned to the lab where he has her test reexamined. A more careful analysis reveals that she has been given a drug that produces results mimicking a brain tumor. With that fact in hand, he and the Five-0 team head for the Institute where they rescue Millicent just as she is about to be frozen.
NOTE: This delightful episode gave Mildred Natwick a chance to reprise her role as Gwen Snoop from The Snoop Sisters series, which she did with James MacArthur's mother, Helen Hayes. One amusing note was provided by having Millicent always call the Governor "Sunny." When McGarrett asked him about that, the Governor shyly replied, "I was a very good natured, happy kid."