Keesha, Robert, Chip, and Kim just joined the astronomy club at school, run by the science teacher, Miss Kepler.
The children are eager to see the planets through the telescope, and Miss Kepler sleepily tells them they would see Mars in twenty minutes.
Miss Kepler then takes a nap in her chair.
Keesha looks through the telescope and finds Barney.
The other children run to greet their purple friend.
Then, Barney and the children look at the stars.
Afterwards, they look through the telescope to find an unusual planet.
On that planet, there is a little girl, and she is waving at them!
The children wish they could meet the little girl, so Barney transforms Robert's toy rocket into a very big one.
Space suits magically appear on the children.
Then, Barney and the children go inside the rocket, countdown to blastoff, then fly off to the unusual planet they saw.
While they are flying through space, Barney explains there is no air in space, no day or night, and that there is no gravity.
Then, astronaut Kenneth S. Reightler, Jr. pays a visit to talk about NASA.
Afterwards, the children see if they can find astronauts on the moon, and they see Baby Bop, with her blankey as the flag.
Barney tells Chip to bring her in, and then Baby Bop joins the journey.
After a while, BJ joins the journey, and soon they arrive at the planet they saw through the telescope.
Then, they meet the girl, whose name is Meebeedeep. Meebeedeep shows the kids around her planet, shows them her toy robot, and Baby Bop teaches her "The Itsy-Bitsy Spider".
Then the kids discover a plant called the tickle tree, which tickles you every time you go near it.
After a while, Barney and the children have to leave, but they promise they will come back and visit.
Then Barney and the kids fly back to earth to go home, and sing "I Love You"