TAS Season 1 Episode 5 More Tribbles, More Troubles

Plot

While the Federation starship USS Enterprise escorts two robot cargo ships carrying quintotriticale, a new seed grain, to famine-stricken Sherman's Planet, it encounters a Klingon battlecruiser, commanded by Captain Koloth, firing on a Federation scout ship. The Enterprise beams the pilot aboard. The Klingons use a new energy weapon which incapacitates the starship, and demand they hand over the pilot. First Officer Spock hypothesizes that such a powerful weapon must require all the Klingon ship's energy, and Lt. Uhura notices that the two cargo ships have not been disabled. Captain Kirk has the cargo ships set a course to ram into the Klingon ship. With their energy expended, the Klingon ship is forced to flee, but damages one of the cargo ships. Since the Enterprise cargo hold lacks sufficient space, the crew must dangerously load the ship's decks with the grain.
The pilot is Cyrano Jones, an interstellar trader well known to Kirk and crew. He got out of his task of cleaning up the tribbles on Space Station K-7 using a glommer, which preys on tribbles. Jones is now selling "safe" tribbles genetically engineered to be sterile. The Klingons attack again, disabling the engines of the remaining cargo ship and bathing the Enterprise in a radiation which rapidly increases the growth of the tribbles aboard. Kirk still refuses to hand over Jones, ostensibly because he is a Federation citizen, but actually because he suspects the Klingons would not have violated Federation space unless Jones were of great value to them. The Klingons again use their new weapon. Kirk responds by having the tribbles beamed over to their ship.
Now at a disadvantage, Koloth admits that Klingon planets are being overrun by tribbles sold by Jones. The glommer, which was created by the Klingons via genetic engineering and stolen by Jones, is their only hope of controlling them. Kirk returns it, but the huge tribbles scare it away. Koloth orders his first officer to shoot the large tribble, only to inadvertently free smaller ones inside. Chief Medical Officer Dr. McCoy, having discovered in advance that the large tribbles are actually tribble colonies, injects the remaining tribbles on the Enterprise with a serum to slow down their metabolic rate.