On the way to a space colony, a crisis sends the Robinsons hurtling towards an unfamiliar planet, where they struggle to survive a harrowing night.

Another crash brings more travelers to the planet, as the Robinsons work to salvage their ship with help from their mysterious new companion.

The Robinsons make contact with another family of survivors; Will races to protect his friend after Judy learns what happened aboard the Resolute.

As the team builds a tower to signal the Resolute, Maureen investigates a planetary anomaly, and Will braces for a tough conversation with his dad.

Maureen debates whether to share what she saw in the sky, Don leads a mission to find fuel, and the robot's presence stokes tensions within the group.

Judy and Don race home across the desert with their precious cargo. John and Maureen are dealt a heavy blow. Penny does her best to comfort Will.

Maureen finds a solution to the fuel issue, but putting her plan into action proves trickier than expected. Dr. Smith realizes her cover is blown.

Judy sets out to find Maureen, while Will and Penny lead an expedition to the caves. Dr. Smith pursues a new escape plan.

The Robinson family scrambles to launch from the Lost Planet, stage an impossible rescue, and reach the Resolute before it leaves orbit for good. Unfortunately, some have other plans.