When an Alien Limpet UFO causes the destruction of Lunar Module 32, Straker demands a clean-up programme by the International Astrophysical Commission to remove hazardous space debris from Earth orbit. But Straker finds himself butting heads with I.A.C. chairman James Henderson, who wants a complete shut-down of SHADO operations...
One Granny plus one Navy frogman equals a running gag: Granny thinks Elly's new beau is a frog.
Linc receives a desperate call from an old friend, now an inmate at a mental institution. Shortly afterward, the friend is dead of "heart failure", only the latest of a number of strange deaths at the place.
Lucy Carter, a widow with two teen children, takes a job as a secretary for her stuffy brother-in-law.
Doc Adams feels that Sam McTavish (who is a woman Doctor) may replace him.
Hogan convinces Klink that he is a great artist so he can smuggle out some maps in the Kommandant's canvases.
In the Middle East Willy and Barney infiltrate a chemical plant to gain access to Dehominant-B, a quick-acting lethal gas. Barney is exposed to Dehominant-A while trying to get to the computer and crippled - Willy escapes and Barney is captured. Barney is interrogated and only has four hours to live. The team find out that Dr. Jerry Carlin, a dropout, is the only other person with the skills to access the computer. When Carlin rejects the team's appeal for help, Jim and Paris frame Carlin's girlfriend and threaten to keep her in jail unless he helps them. Dana provides a distract and Paris takes the head scientist Vazan's place and have Barney first fake a confession implicating the technicians and then his own death - they get Barney to the autopsy room where Doug revives him in the nick of time. Jim and Carlin take the incriminated technicians' place and Carlin manages to ruin the Dehominant and erase the computer, then everyone escapes with Vazan.
When Phyllis's husband Lars takes ill, she asks Mary to babysit Bess for a few days. Bess decides she wants to stay permanently with Mary, to Phyllis's dismay.
While driving to the barnyard dance, the gang finds an injured bank guard. He gives them a blank paper and says something about a flame. The gang learns of a local bank robber called the Creeper. Things take a serious turn when the Creeper tries to steal the blank paper.
The Pussycats search for the Evil Eye, a mysterious figure with hypnotic powers, who has kidnapped Valerie and an Arabian princess.
Mike and Carol decide to allow Greg and Marcia babysit for the younger Bradys one evening when they go out for the evening and Alice is out with Sam.
A half-breed Indian lad whose life has been saved by men of the Cannon ranch strives to repay the debt. John Cannon, Buck and Manolito intervene when ranchers Fraley and Henderson attempt to hang Wind, whom they accuse of rustling cattle. The boy's indebtedness later figures significantly in the defense against a series of mysterious and costly raids on a major cattle drive.
During home guard manoeuvres LCpl Jones, disguised as a log and helped by Frazer in a diving suit, floats down the river in order to attack the Eastgate platoon's headquarters.
A minor fender bender turns into a major pain for the Partridges when they decide to fight a fraudulent lawsuit from Whiplash Willie. Guest Stars: Harry Morgan as 'Whiplash' Willie Larkin and Farrah Fawcett Song: "I'll Leave Myself a Little Time"
Samantha and Darrin are under close supervision by Hepzibah. How is it possible for a witch and a mortal to be married and happy at the same time. Hepzibah then meets a client of Darrin's named Ernest Hitchcock and, thanks to Samantha, Hitchcock falls for the Priestess. The Priestess then rules out that the witch/mortal marriage is a great thing after all when she invites Sam and Darrin to go to Salem.
The Chief travels into the mountains to spend the weekend with an old friend, only to be snowed in following a bad blizzard. Trapped in a small cabin, Ironside discovers that his friend is now an addict, violent and unpredictable without the fix he cannot get.
Dr. Lemira, an opposition leader for Greece, is living in exile in Hawaii, but Klaus Marberg is sent to assassinate him. His plan is to get himself shot and work his way into Dr. Lemira's confidence so he can kill him easily. McGarrett must work out this plot and save the day before it is too late.