Star and the Diazes arrive in the forest for a camping trip. Star is already excited, and Marco looks forward to doing some fishing, hiking, and seeing Old Youthful, one of the oldest geysers on Earth—which is scheduled to erupt that day. Since Marco's parents are busy making paintings for their slideshow, it is just Star and Marco for the rest of the day. Suddenly, something falls from the sky and crashes into the ground. Star and Marco discover that it is Star's father, River Butterfly, who has come to join them on their camping trip.
They start the day with some fishing, which is short lived after River Butterfly jumps into the water and tries to catch fish with his bare hands. Next, they take a hike in the woods looking for Old Youthful. Walking on his hands, River Butterfly wanders off, and Star and Marco find him having a staring contest with a Bald Eagle. They end up getting in trouble with the park rangers for disturbing the wildlife, and Star and Marco begin to think that something is bothering River Butterfly.
The three soon get back on their way to see Old Youthful, but after River Butterfly eats the map they lose their way and end up fifty miles away from Old Youthful. After River Butterfly gets them in trouble again with the park rangers for hitching a ride on a grizzly bear, Star has had enough of her father's weird behavior and apologizes to Marco for not being able to see Old Youthful. But Marco reveals that he has already seen Old Youthful a dozen times and wanted Star to see it. Because she has shown him many amazing things, he wanted to pay her back by showing her something amazing on Earth. When they hear from the park ranger that Old Youthful is going to erupt for the last time, River Butterfly decides to carries Star and Marco all the way there. With Star and Marco on his shoulders, he runs ten miles all the way to Old Youthful in under five minutes, but they miss the last eruption by mere seconds. River Butterfly feels ashamed and admits he has been acting weird because he feels down about his age and that Star is growing up. However, Star and Marco are very impressed by how far he ran, and Star tells her father that he will always be her hero no matter how old she gets.
Just as they are about to make their way back, River Butterfly falls into the geyser, which suddenly erupts to life. As it turns out, the park ranger lied about the geyser erupting one last time, and Star finally gets to see Old Youthful in full glory and be amazed.
- Eden Sher as Star Butterfly
- Adam McArthur as Marco Diaz
- Alan Tudyk as River Butterfly
- Artt Butler as Mr. Diaz
- September 1, 2016 (United Kingdom and Ireland)
- November 11, 2016 (Italy)
- November 27, 2016 (Japan)
- December 16, 2016 (Southeast Asia)
- December 16, 2016 (Latin America)
- January 6, 2017 (Poland)