The Trouble with Tribbles

The Enterprise is diverted to Space Station K-7 to protect an important shipment of quadrotriticale, a specialized grain. Captain Kirk finds his responsibilities and his patience severely taxed by Federation Undersecretary of Agricultural Affairs Nilz Barris and his pesty assistant, Arne Darvin. The arrival of a Klingon ship, commanded by the arrogant Captain Koloth, does not make matters easier for Kirk. He must grant the Klingons permission for rest and recreation on K-7 under the terms of the Organian Peace Treaty, while protecting the glorified wheat. Kirk's real problem turns out to be space trader Cyrano Jones, a dealer in rare commodities including tribbles. Tribbles, living fluffballs that do nothing but coo, eat, and multiply, soon threaten to overwhelm the Enterprise and space station. The tribbles get into the grain bins and devour the wheat (correction: quadrotriticale). Widespread tribble casualties reveal that the grain was poisoned by Arne Darvin, whom the Klingon-hating tribbles expose as a Klingon. A disaster is prevented and a Klingon agent is exposed, thanks to the tribbles, which Kirk compels Cyrano Jones to remove from the space station. Scotty beams the Enterprise's crop of tribbles to the Klingon battle cruiser as a parting gift.