E1 - The Reluctant Stowaway

Aired: September 15, 1965

In the year 1997 the Robinson family take off to colonize Alpha Centauri. A spy from a foreign country AKA Dr. Smith becomes trapped aboard trying to sabotage the project. The ship is whisked off course and into a meteor storm due to Dr. Smith's extra weight upsetting the navigational computers. Smith desperately tries to save himself by reviving the crew. The result: the Robinson family becomes lost in space.

E2 - The Derelict

Aired: September 22, 1965

The Jupiter 2 is pulled into a giant alien spaceship where there are advanced bubble-like creatures. While John and Don look for maps and equipment Dr Smith and Will look for trouble.

E3 - Island in the Sky

Aired: September 29, 1965

Professor Robinson attempts to explore a planet that the Robinson's are planning to land on. His para-jet propulsion system fails due to sabotage by Dr. Smith. Major West "lands" the Jupiter II, in spite of the fact that Dr. Smith has also sabotaged the propulsion system of the Jupiter II, and the family and Major West rescue Professor Robinson.

E4 - There Were Giants in the Earth

Aired: October 06, 1965

John discovers that the planet they are on will travel further from the sun.In an attempt to survive the Robinsons pack up and head south. Dr Smith stays at the Jupiter 2 site while the Robinson family encounter a terrifying cyclops and an ancient deserted city.

E5 - The Hungry Sea

Aired: October 13, 1965

Professor Robinson discovers that the planets orbit will bring immense heat on the spaceship. With that knowledge the Robinson's take off in the chariot and head south. However back at the Jupiter two, Dr Smith who stayed behind because he believed them to be lying, realises that the orbit is strange, bringing immense cold followed by extreme heat. He sends the Robot to tell them, and they then attempt to travel back to the Jupiter 2. However in their way is a huge in-land sea which previously had been frozen solid. The immense heat and cold make the vegetation charred. They survive the heat and return to the Jupiter Two where they are most safe.

E6 - Welcome Stranger

Aired: October 20, 1965

Jimmy Hapgood lands on the planet and the Robinsons befriend him. After helping him fix his spaceship the Robinsons try to convince him to take Will and Penny back to Earth with him. Dr. Smith tries to get aboard the ship instead and take their place.

E7 - My Friend, Mr. Nobody

Aired: October 27, 1965

Penny "imagines" a new companion, which is a disembodied life force living below the surface. Dr. Smith accidentally injures Penny, leading to the creature taking his anger out on the entire planet.

E8 - Invaders from the Fifth Dimension

Aired: November 03, 1965

Luminous aliens capture Dr. Smith and plan to replace their burnt out computer with his brain. Smith bargains with them and they attempt to use Will's brain instead.

E9 - The Oasis

Aired: November 10, 1965

Dr. Smith eats some alien fruit which transforms him into a giant. Convinced it was the Robinsons trying to kill him, he plots to take them out.

E10 - The Sky Is Falling

Aired: November 17, 1965

The Robinsons can not understand the language of a visiting family also on the planet. The aliens are called Taurons, and come to use the planet as a new colony. However Dr. Smith causes problems between the two camps when he panics and draws a gun on the new family. The Taurons end up not liking the planet and want to be alone, so they leave.

E11 - Wish Upon a Star

Aired: November 24, 1965

The Robinson family banish Dr. Smith from the Jupiter 2. He takes refuge in an abandoned spaceship where he finds a machine that can materialize anything. In an attempt to get back on the Robinsons good side he gives them the machine which plays on the family's greed.

E12 - The Raft

Aired: December 01, 1965

Actually, Will and Dr. Smith went into an elongated orbit and landed right back on the planet, not too far from the Jupiter II.

E13 - One of Our Dogs Is Missing

Aired: December 08, 1965

The women of Lost in Space are featured in their very own episode while the boys are out installing communications equipment. Smith is left in charge (boy is that a mistake) and he "cleans" their weapons, but cannot remember how to rebuild the weapons. This leaves the J2 crew defenseless. A creepy creature stalks the Robinson women however they think a small dog is to blame for raids on food and other mischief.

E14 - Attack of the Monster Plants

Aired: December 15, 1965

Plants grow to huge proportions and can duplicate any item placed in them - but those items are made of plant material and are useless. John Robinson must use the biggest batch of plant killer he's ever mixed up to stop these things from engulfing the spaceship.

E15 - Return from Outer Space

Aired: December 29, 1965

Lost in Space's only Christmas program. Will uses an alien transporter to send himself back to earth. However, many people believe the Robinson family to be dead after hearing the ship went off course. Nobody on Earth believes him, and they lock him up with the intention of sending him to a boys' home. Will escapes the family home he's in, and wanders around these clueless bunch of townspeople, but finds carbon tetrachoride — needed for the food processors on the Jupiter. Eventually he convinces another boy, Davey, to let him out, and let him return to the planet he came from. He returns to Priplanus with this bottle. Of course no one believes his adventures until he produces the bottle, plainly labeled as coming from Earth.

E16 - The Keeper (1)

Aired: January 12, 1966

The Keeper, played by Michael Rennie, is a zoo keeper. He wants to take the children and add them to his collection. This episode is the only two-parter from the series.

E17 - The Keeper (2)

Aired: January 19, 1966

The second part of the zookeeper played by Michael Rennie. Rennie turns in a memorable performance as The Keeper. His understated performance keeps dramatic tension where none would probably exist with a lessor actor.

E18 - The Sky Pirate

Aired: January 26, 1966

The Robinsons meet a space traveler who turns out to be an Earth man, Alonzo P. Tucker, who was abducted from Punxsutawney, Pennsylvania, by aliens, in 1876. Tucker befriends Will by telling tall tales about being a pirate, but it turns out that he is only an ordinary man being pursued by aliens because he has stolen a mind reading device from them. Tucker returns the mind reading device to his alien pursuers, saving the Robinsons in the process.

E19 - Ghost in Space

Aired: February 02, 1966

Dr. Smith holds a seance to contact his Uncle Thaddeus. Instead a spirit creature is contacted and creates havoc for the Robinsons. It is later discovered that the ""spirit creature"" is a physical creature, rendered invisible by the properties of the ""ionized gas"" in the bog from which it came.

E20 - War of the Robots

Aired: February 09, 1966

Will and Dr. Smith stumble upon another robot. More capable than their own robot the alien robot works to gain the confidence of the Robinsons. At a critical point he plans to transport them to his home planet as slaves.

E21 - The Magic Mirror

Aired: February 16, 1966

Penny and Judy stumble upon a mirror. They discover someone is on the otherside. Before they know it they are transported to the mirror universe which is occupied by only one person, a boy who is lonesome for companionship.

E22 - The Challenge

Aired: March 02, 1966

An alien boy is sent to Priplanis to validate his prince status. Will is drawn into a battle to the death unbeknowest to his father. Once his real intentions are known John substitutes himself in the challenge and the Alien Ruler substitutes himself for his son.

E23 - The Space Trader

Aired: March 09, 1966

After the entire Robinson food supply is wiped out in a freak storm a trader arrives to trade food for equipment the Robinson's possess. Dr. Smith trades the robot for food and hoards the supplies for himself. Later, after the Robinson's discover his transaction he gets the robot back but in exchange for his own self. The Trader then wants to take Smith as a slave, to another planet.

E24 - His Majesty Smith

Aired: March 16, 1966

Dr. Smith is conscripted as the leader of a people from another world. Little does he know that the leaders of these people are routinely sacrificed and replaced with other expendible leaders. Smith is just one of a long line of sacrificed rulers.

E25 - The Space Croppers

Aired: March 30, 1966

The Beverly Hillbillies move to Priplanis. One of the aliens turns into a werewolf at night. The leader is a articulent female which Smith tries to court so he may have transportation back to earth. Don falls for the sexy alien daughter.

E26 - All That Glitters

Aired: April 06, 1966

In this retelling of "The Midis Touch", Dr. Smith gains the power to turn anything into platinum. Penny is given a gift by a thief on the run, who tells her to protect it for him. She and Dr. Smith discover that it leads them to a ring which, when worn, allows the person to turn anything to platinum, which Dr. Smith does and enjoys. However, when it turns even his food to platinum, he is unable to remove the ring, which is now a solid bar. He leaves the camp as he fears turning everything into platinum, and he will eventually starve to death. A galactic lawman is on the trail, looking for the stolen device to use for his own nefarious purposes.

E27 - The Lost Civilization

Aired: April 13, 1966

The Robinson men discover an underground civilization while exploring the planet. Will wakes a sleeping princess who wants him to remain and rule with her.

E28 - A Change of Space

Aired: April 20, 1966

The Intergalactic Delivery Service comes to Priplanus. Once again Dr. Smith seeks transportation and has Will "test drive" the spaceship. Will returns much smarter than when he left. Smith realizing the same could happen to him, the increase of intellect, boards the spaceship. His trip, however, ends in his rapid aging and subsequent impending death. To make matters worse, the owner of the spaceship has returned to take the vehicle back, stranding Will and Dr. Smith in their altered state.

E29 - Follow the Leader

Aired: April 27, 1966

John Robinson is possessed by an alien spirit. The alien forces the family to prepare to return to the spirit's home world, even if it requires he sacrifice Will to keep his secret from the rest of the family.