The last thing College Lit Professor Cary West wants, while is wife is out of town, is a TV set to keep him company; but that's just what wife Carolyn has bought for him. He is relieved when the serviceman returns to collect the $100 deposit Carolyn forgot to give him; good, he doesn't have the money so the man can take the TV back! Only, a $5 bill he accidently dropped on the floor near the TV has suddenly developed 19 siblings, and the serviceman leaves, cash in hand. West soon realizes he has a major problem: the TV is alive. It lights his pipe, washes his dishes, vacuums his rugs. It also chooses what he can read, write, and marches around to military music; and It also zaps anyone who tries to harm Cary in any way, such as treasury agents investigating the duplicate $5 bills, the police who investigate a call placed by the TV set to the phone company requesting a 'female companion' be sent over for Cary's comfort, and a female bill collector who decides to move in til Cary pays his wife's bills. Cary's sole confident in the adventure is is Gym Coach Trout, who theorizes the set is inhabited by a thing which has time-travelled from some authoritarian society of the future and landed in the TV by accident - a 'twonky' he calls it. Now the only thing to figure out is how to get rid of it, since the Twonky also has the capacity and willingness to defend itself above all else, even serving its master Cary...