The U.S.S. Potemkin obtains the drug and transports it to the U.S.S. Huron, en route to the Enterprise. Without warning, the U.S.S. Huron is attacked by a vessel of Orion designation and the drug and a cargo of dilithium crystals are stolen. The U.S.S. Enterprise encounters the Orion ship in a volatile asteroid field by detecting the dilithium crystals in the ship's cargo bay. Kirk attempts to negotiate for the drug in exchange for not mentioning the stolen dilithium crystals, but the Orions' suspect a ruse. Kirk agrees to meet the Orion captain on an asteroid knowing that it might be a trap, but worth the risk for Spock's life.

The Orion captain arrives carrying a bomb capable of destroying the entire asteroid but Scotty beams the explosive to the Enterprise and discharges it. Scotty then beams up the two captains and forces the Orion captain to stand trial for piracy. With the medicine in hand, Spock is saved.