Nearly a year after the events of the Season 2 finale, the kids and adults are still separated. The youngsters (and Smith, who secretly snuck aboard their ship) are on a planet close to the Fortuna, trying to repair the Jupiter. The adults, on the other hand, are essentially stuck — needing to obtain a new robot engine, but aware of the dangers they might face if they steal one. What will it take for them all to reunite?

Key Players:

John Robinson (Toby Stephens): The Robinson patriarch struggles with his kids being gone and his wife pulling away in their absence.  

Maureen Robinson (Molly Parker): Maureen is haunted by her separation from her kids, throwing herself into work to avoid the pain.

Judy Robinson (Taylor Russell): Judy has dueling new responsibilities as she serves as captain/leader of the stranded children and reunites with her presumed-dead biological father.

Penny Robinson (Mina Sundwall): The middle Robinson child finds herself in the middle of a love triangle with quasi-ex Vijay and new guy Liam. 

Will Robinson (Maxwell Jenkins): The youngest Robinson is ready to take care of the robot-human war on his own terms.

June Harris/Zoe Smith (Parker Posey): The quasi-reformed criminal becomes caretaker to the kids in the year they spend separated from their parents.

Don West (Ignacio Serricchio): The mechanic grows closer with John and Maureen as the adults try to figure out how to reunite with the kids.

Robot (Brian Steele): An alien robot who will sacrifice everything for Will.

Key Locations:

Jupiter 2: The Robinsons’ ship/home base, which is now the hub for the adults on the mission.

Jupiter: The ship housing the 97 kids (and Smith). 

Key Plot Points:

1. Judy finds her biological father, Grant, essentially frozen aboard the Fortuna. Though he had no clue she existed, the two bond with each other.

2. As the children are working to fix their ship, their timetable is thrown aside when the asteroids surrounding the planet become a danger. With the addition of Grant on board, there is not enough oxygen for the group, so Smith is chosen to be put into his former chamber for the duration of the trip. 

3. The adults are desperately looking for a new engine. John and Maureen are briefly able to speak with their kids via their respective robots, but things seem grim until the kids show up and save their lives.

4. Will discovers a mass alien grave and realizes they built and programmed the robots. He also realizes this war will never end unless he stops it. After he reunites with his family, his plan is to take Robot and go to SAR, the robot who has been gunning for him. They meet face to face, and Will tells SAR that the creatures that programmed robot-kind are gone, so they can choose their own future now. But SAR has his own curveball: He knew that already because he killed his masters. SAR attacks Will, damaging his heart. 

5. SAR and the robots scan Don’s body, which Maureen realizes gives them a road map to Alpha Centauri. They get there ASAP and try to protect the settlers who are already living there.

6. When Will’s new artificial heart seems to be failing, Robot creates a safe space for the duo and puts a piece of himself in Will’s mechanical organ: Basically, Robot is sacrificing himself to ensure Will survives (sob). After attacking Alpha Centauri, SAR — who wants to destroy humanity with a bomb — goes for Will’s heart again, but it’s a trap. Robot takes over SAR’s being, allowing him to save everyone.

7. The rest of the robots break free of their programming, and most opt to leave to go off and do their own thing. With everything peaceful on the now-trashed Alpha Centauri, Penny continues writing, Will and Robot go exploring in space, Maureen and Don work on building another ship to replace the Resolute, John enjoys the quiet, Judy continues as a doctor and Smith is locked up.