Danger, Will Robinson
Directed by David Nutter
The Robot, now resurrected and under Dr. Smith's control, appears to be taking the engine from its ship. The star map activates and pans across to a view of the planet from space, revealing Don and John clinging to a piece of debris from the shattered Jupiter, lamenting their plight as they slowly run out of air. John is in contact with Will via their transmitter and learns through Morse code that they've discovered fuel. "Fuel, they have fuel!" "Yeah, so we went up here for nothing." Irony.
Will and Penny are preparing their own Jupiter for launch, having snuck out of Hiroki's ship. They are determined to wait for Judy and Maureen. They show up, finally, but with an unwelcome guest: Dr. Smith. Penny says it's four against one, but then the Robot steps out. Will is overjoyed at first, but his joy turns to shock when the Robot knocks him down. It's either forgotten him or resents him. But Maureen learns that John is alive, and insists on rescuing him, despite the risk of missing their rendezvous with the Resolute. Smith reluctantly agrees.
As the launch counts down, Will tries to get the Robot to remember their friendship, unsuccessfully. He begins to lose hope, but then the earth shakes again. A volcano erupts nearby, either another symptom of the planet's tectonic instability or one last attempt to keep them from leaving. They take off anyway, punching through the ash cloud and reaching orbit.
Maureen starts a search program to find John but there's not enough fuel. Dr. Smith insists they abandon him. A contest of wills ensues that Maureen wins by diving the Jupiter towards the planet. She knows the Robot will try to protect Smith, which it does by forcing her into the ship's hub, its safest place. Maureen stabilizes their orbit and locks down the hub, trapping Smith inside, but she knows it won't last forever. She sends Penny and Judy to prepare the ship's harpoon (much to Penny's amusement) and keeps Will with her.
Will's anguish comes to a head and he finally confronts his mother with the question he's always been afraid to ask: Did he fail the test to get in the colony program? He feels responsible for everything that's happened since they crashed. Maureen tells him the truth, and he tells her that he should never have come along. Despair looms.
On the debris, Don is trying to rig the remaining electrical systems to emit a jet of hot gas, signaling their location, but his eye is injured by a flake of anti-fogging agent. John has to do the work under his guidance, but the task proves difficult. Don has to cry to restore his eyesight, and John finally manages to move him to tears by describing his love for his family, something Don's never experienced. They send out their flare, and Maureen sees them. The harpoon is ready and the distance is closing, but Smith's found out how to unlock the hub. Maureen and Will flee, but the hastily fired harpoon comes up short. Smith sends the Robot in pursuit of the family while she blames them for all her misfortunes.
In the garage, Maureen shoves the children into the Chariot while she prepares a desperate plan, but Will remains outside. He confronts the Robot one last time, demanding it recognize him. It attacks him instead, just as Maureen slams it with the assembly armature, knocking it onto the ramp. She opens the ramp, dumping the ship's air into space along with the Robot. They're safe.
But then an ominous droning starts. A second alien ship appears, the ramp is forced back open, and two robots climb aboard. They sent backup. Maureen is knocked out by the new robot, which blasts the Chariot to uncover the alien engine hidden beneath it. A ricochet damages Will's suit and injures him. The new robot is about to kill him when Will's Robot restores its memory and fights the other alien. A battle ensues in which both are knocked out of the ship.
Maureen is injured and her helmet is cracked. The Chariot's seals are damaged and it's leaking air. The ramp won't close. Will, whose suit was fixed by the Robot, is the only one left who can climb outside and manually close the ramp. Now, Let Me Carry You, he says to his mother. He succeeds in closing the ramp, but when he tries to climb to the Jupiter's rear hatch, his injured arm betrays him and he loses his grip. It seems as if he's doomed, when John shows up to catch him.
Back aboard, the family takes a moment to relax. They're together, but the Resolute is gone. Maureen realizes that Smith must have fired the harpoon again to rescue John and Don. "Why did you do that?" she asks the woman who is now imprisoned in the airlock. Smith doesn't have a good answer. And the family is stranded in orbit, with no good options... until the Resolute shows up. Victor waited for them.
They barely have time to rejoice, though, before something weird happens. The alien engine, which had previously been providing them with artificial gravity, takes over the ship's controls, and its engines. It opens a wormhole and the Jupiter falls in, spilling them out in an unfamiliar system with a weird double-star. Will recognizes this... from the Robot's drawing in the sand, and the one word it offered by way of explanation: "Danger."
