Tom and Jerry are selected to go into a Space shuttle and a Scientist is testing if They can live in Harmony in Outer Space.
In the final cartoon of the series, a scientist is holding a press conference at the launch site of the space shuttle USS Unnecessary. The Unnecessary is about to launch with an experiment to put two historic enemies in a confined space ship environment to see if they can get along in the hopes that everyone can learn and live in peace with each other. Tom and Jerry are the test subjects for this historic mission. Once in space, the cat and mouse begin to float around the cabin for a little weightless fun, but Jerry starts to mess with Tom by spinning him like a top. Tom ends up getting strapped into his chair while Jerry plays around weightless. Tom recovers and returns the spinning favor to Jerry who bounces around the cabin all the while the Scientist is watching on the monitor mortified. The Scientist yells at the cat and mouse crew to stop messing around and behave. The first experiment is grooming. Jerry must resist his natural inclinations with scissors as he must groom Tom. Jerry cuts up Tom's hair and writes Stinky.
With this test a failure they move on to the next one, eating together. Tom prepares the meal but ends up squirting astronaut food at Jerry. He retaliates with a pie, but Tom eats a watermelon and tries to shoot the seeds at Jerry. With this test failed, the next test is the educational test. A True/False Q&A is set as Tom and Jerry answer questions about cats and mice which devolves into a sword fight with the pointer sticks the two were using. The Scientist keeps interjecting the fights by saying that the two must live in peace and harmony. Finally, the shuttle lands after a few days we find out that our two antagonists finally put their difference aside and live in peace and harmony. Tom and Jerry are presented with a trophy for their success and as they leave the landing site, Tom starts chasing Jerry with the trophy to bash the mouse with. We find out that the Scientist's next experiment is to send an elephant and chicken into space while Tom and Jerry continue their chase as the screen fades to black at the series finale of Tom & Jerry Kids. And now the series is over, the spin-off series will begin, called Droopy, Master Detective!