The episode opens as the Enterprise is headed back to Sherman's Planet, this time escorting two robot ships carrying the grain quintotriticale, obviously a new form of the original episode's quatrotriticale, to the colony's famine stricken population. Along the way, they encounter a Klingon ship firing on a small Federation cargo vessel. The Enterprise manages to rescue the cargo ship's pilot, who turns out to be troublemaking trader Cyrano Jones, but not before getting hit with a new Klingon superweapon, a stasis field ray that temporarily knocks out the ships engines and weapons.
Jones arrives on board the Enterprise carrying what he says are "safe" tribbles. These ones do not reproduce at an accelerated rate like the ones seen in the original "The Trouble With Tribbles". Instead, when fed, they grow to enormous proportions. However, inside each giant tribble are hundreds of smaller tribbles, so the ship is shortly once again overrun with the furry nuisances.
The Klingons are after Jones for stealing the only prototype of their genetically engineered tribble predator, known as a glommer, and demand that Kirk turn the trader over to them. Kirk refuses, but does give them the glommer. However, the creature ultimately proves ineffective against the giant tribbles after Kirk once again dumps all the tribbles on the Klingon ship.. Equally ineffective is the Klingons' stasis ray weapon, which uses up too much energy to be of much use in battle.
There are many problems with this episode. The first is that there are two parallel stories being told and neither is given time to fully develop. The plot concerning the new Klingon weapon ultimately goes nowhere while the Cyrano Jones/tribbles story line adds nothing new to the original episode. In fact, from the tribbles overrunning the ship, to thousands of them once again falling on Kirk's head, to cleaning up the Enterprise by beaming the tribbles over to the Klingon ship, to ending with a bad tribble pun, its pretty much a beat for beat remake of the first "Tribbles."
The worse problem is that, for a supposed comedy, the episode just isn't funny. This isn't entirely the fault of the script, as bad as that may be. Even though Gerrold says in his commentary that at the recording the cast seemed happy to be back doing Star Trek again, it doesn't quite come across in the vocal performance. The line readings throughout the series tend to be a bit flat, as if the cast had attended the Jack Webb School of Acting during the series' hiatus. (On Dragnet, Webb discouraged his actors from learning their lines, preferring that they sound as if they were reading from cue cards, which, in fact, they were.) This certainly doesn't help to sell the humor, and these "jokes" need all the help they can get.
The tribble predator, the glommer, is just plain silly. It looks more like something you'd see in a more typical Saturday morning cartoon than in Star Trek. It even does that Scooby-Doo running in place thing at one point.
Stanley Adams returns to the role of Cyrano Jones for this episode. Unfortunately, William Campbell did not return to the role of the Klingon captain, Koloth. James Doohan takes over the role here, but he fails to capture the smarmy charm of Campbell's performance.
One other thing worth noting about this episode is that the tribbles are colored pink, not brown as they originally were. This is apparently due to the fact that director Hal Sutherland was color blind. This kind of works for the cute little tribbles, but when the Klingons end up wearing pink vests and a fierce race of warriors known as the Kzinti are flying around in pink ships, then it gets a little ridiculous.
"More Tribbles, More Troubles" is a well intentioned effort to produce a follow-up to one of Trek's best and most beloved episodes, but nonetheless an effort that ultimately fails.