has suffered an outbreak of choriocytosis, but the disease is not any more fatal then pneumonia. The ship proceeds to the dedication ceremonies of the Academy of Science on Deneb V. However, Spock collapses while working on the bridge. McCoy has him taken to Sickbay and confirms that choriocytosis is fatal to races with copper-based blood. There is only one cure, a rare naturally-occurring drug called strobolin. The nearest supply planet is too far away for Spock to survive. Even with a synthetic version of strobolin, McCoy can only sustain Spock for three days. McCoy suggests they set up a rendezvous.
Kirk arranges for the Potemkin
to deliver the drug to a freighter, the S.S. Huron
, which will deliver the strobolin to the Enterprise
. Kirk informs Spock of the rendezvous and cuts his duty time in half. McCoy agrees and Spock leaves.
is proceeding to the rendezvous when they pick up a ship on the long-range sensors.
puts on best speed and Spock is called to Sickbay for another treatment.
The unidentified ship approaches Huron
and moves to intercept.
McCoy continues to treat Spock with the synthetic strobolin but soon realizes that the drug is having no effect.
Captain O’Shea of the Huron
tries to hail the approaching ship. It refuses to hail and they’re unable to evade. They send an emergency signal to the Enterprise
and the aliens tell them to surrender their cargo of dilithium or be destroyed.
receives the Huron
’s distress signal and accelerates. They arrive to find the Huron
heavily damaged by the enemy attack. Spock collapses and is taken to Sickbay where McCoy informs Kirk they’re running out of time. They detect life signs and Kirk beams over with Chapel, Uhura, and Scott to look for survivors. They confirm that the Huron
crew is barely alive, and the dilithium and the strobolin has been taken. Spock has only 20 hours left until the disease proves fatal.
Arex analyzes the Huron
’s ship logs and determines they produce a unique trail of radioactive waste. While Spock’s condition worsens, they follow the trail into an asteroid belt. The radioactive waste ends in the middle of the belt. The Enterprise
goes to red alert and then discover that the asteroids are a mix of matter and anti-matter, and prone to detonation. As they proceed through the belt, the alien ship opens fire. Their phasers are too weak to penetrate the ship’s shields. Arex identifies the ship as an Orion vessel.
The Orion captain hails the Enterprise
and demands that they end their pursuit. He tries to claim neutral status but Kirk points out that Orion’s neutrality has been in dispute since the Babel conference. Kirk demands they submit to a search per the Babel resolutions but the Orion captain refuses. They detect the dilithium aboard the Orion vessel and Kirk offers a proposal. If the Orions turn over the strobolin, Kirk will let them go, keep the encounter off the records, and give them additional dilithium. The Orion captain agrees to consider the matter. After a few minutes, he makes a counterproposal: a face-to-face exchange on a nearby asteroid.
With Spock only having an hour left, Kirk agrees to keep the proposal but keeps his communication wavelength open and has Scotty monitor him constantly. Meanwhile, the Orion captain confirms he can’t escape. They can’t trust Kirk’s word and the only way to preserve Orion’s neutrality is to destroy the Enterprise
and themselves. They plan to convert the nearby asteroid into a bomb capable of destroying both ships. However, the only thing that will suffice is a powerful explosive on the asteroid’s surface. The Orion captain decides to go down himself to assure that the Enterprise
Kirk accepts the offer and the two captains beam down to the asteroid. Kirk confirms the Orion captain has the strobolin. But the Orion captain informs him that they can’t rely on his word. As he explains his plan, Arex on the Enterprise
senses the dilithium the Orion captain is using to set off the explosion. Kirk wrestles with the Orion captain to stop him from setting off the destination, while Scotty beams up the dilithium. The Orion captain activates the trigger device just too late. Kirk has Scotty then beam him and his rival up to the planet.
Aboard the Orion ship, the second-in-command realizes their plan has been thwarted and arms the self-destruct. Kirk has the Orion captain brought to the bridge and stops him from committing suicide. He informs the pirate that his crew will die for nothing because they’re going to keep the Orion captain alive to stand trial. The Orion captain orders his people to surrender.
proceeds on its way and Spock recovers. McCoy gloats about how Spock’s blood endangered him for once, but Spock refuses to acknowledge any lack of inferiority.