On board The Orville, Dr. Finn is rudely awoken by her son Ty who is excited about a visit to a play planet called Arboreous Prime. Her other son, Marcus, is less enthused.
The Orville is being sent to a dock yard while the Finn are on holiday. Since LaMarr isn't available to pilot their shuttle, Grayson sends Isaac to be their pilot which Dr. Finn is not thrilled by.
Isaac observes the boys' interactions as well as Dr. Finn's parenting techniques. Dr. Finn reveals that she is a single mother by choice and Isaac concludes that she conceived the boys through artificial impregnation.
The shuttle experiences a gravity sheer and when the boys' toy gets thrown onto the navigation controls, they get sucked into a spacial fold and travel a thousand light years away. The shuttle is badly damaged and they make an emergency landing on a moon. in the final approach, Dr. Finn's part of the shuttle is separated from the boys and Isaac.
Isaac is unable to contact Dr. Finn upon landing. Marcus has a dislocated knee which Isaac repairs with no bed side manner. Ty wants his mother and Isaac agrees they need to find her.
At the other crash site, Dr. Finn is unconscious. Someone drags her away.
Isaac arms Marcus and leaves the boys at their crash site to find Dr. Finn. As it gets dark, the boys are frightened by something in the woods. Ty gets grabbed by an indigenous life form but is rescued when Isaac returns and shoots the abductor.
Back on the Orville, the engineering team is installing the new navigational array to the music of Barry Manilow. They are notified that Dr. Finn's party never reached Arboreous Prime and Mercer orders the ship to the last known coordinates. LaMarr points out that the navigational array isn't operational yet and Mercer tells him he'll need to use star charts in the meantime.
Trying his hand at parenting the boys, Isaac inspects the shuttle and diagnoses a depleted diazonium supply which means no long-range scanners or communications. Marcus remembers from school that diazonium can be found in a variety of places and encourages Isaac to scan the immediate vicinity to see if there some nearby they can use. Isaac finds traces on the damaged hull and realizes there must be a deposit in the mountains they flew through during the crash landing. Because it is late, he decides the three of them will go in search of the deposit in the morning.
Dr. Finn wakes up on a pallet in a locked room. When the door opens, the man outside offers her food. She is frantic to find her sons but is prevented from leaving by the man. He locks the door when he leaves but she notices a covered window she thinks she can escape through.
As Isaac and the boys head towards the mountains, they are waylaid by a group of people who demand the boys. Isaac refuses and stuns them all into submission. They continue on.
Dr. Finn is interrupted in her escape attempt by her captor, Drojan, who insists that she eat the food he brought her. When she asks for her communication device he explains that the boys are doomed since the planet's water supply was poisoned by the combatants of a terrible war.
Isaac and the boys wade through a river in their mission. Ty trips and is completely submerged in the water. They continue on.
The Orville finds the spacial fold the shuttle was sucked through. Mercer sends them through blind in order to find out where the shuttle went. The Orville suffers some damage but is operational. When their hails go unanswered, they start searching the nearby moons that can sustain an environment.
At their campsite, Isaac tells the boys a story in their mother's voice. At the same time, Dr. Finn manages to remove the window covering only to discover that she is very high up in a structure.
In the morning, Marcus wakes Ty up only to find his face covered in sores. He complains of feeling sick.
In her cell, Dr. Finn cuts herself in order to get medical attention from Drojan. She convinces him to get supplies from her shuttle to disinfect her wound. While he is gone, she crawls out the window and makes her way along a ledge to a balcony space and then into the living quarters. Finding her communicator, she is able to contact Isaac. They are on their way back to the shuttle crash site with the diazonium. Isaac lets her know that Ty is sick. Marcus apologizes for being a jerk.
When Drojan returns, Dr. Finn ambushes him and shoots him to survive. On her way to the shuttle's coordinates, she shoots a diseased attacker and then take a sample of his blood. When she continues on, she is pursued by several other feral indigenous people.
Making it to the shuttle, Dr. Finn examines Ty and realizes that he may die. Isaac comforts her by holding her hand, something the boys taught him. Isaac is able to send out a brief distress signal.
The Orville picks up the signal and sets a course. They notice that about two dozen attackers are converging on the site.
Isaac and Marcus try to hold off the attackers. They are just about overwhelmed when a shuttle from the Orville arrives and fires on the attackers, driving them off.
Back aboard the ship, Dr. Finn is able to cure Ty and Grayson asks for the antidote so they can help the people on the moon.
Dr. Finn visits Isaac in Engineering and thanks him for taking care of the boys. Ty misses him and Isaac agrees to visit him in sick bay later in the evening.