A planet where Federation Assistant Commissioner Nancy Hedford was working to prevent a war when illness forced her removal, setting up the events of Metamorphosis.
Epsilon Canaris III is mentioned in the Original Series episode Metamorphosis. Assistant Federation Commissioner Nancy Hedford has been sent there to stop a war from breaking out, but she contracts Sakuro's disease, a rare and deadly illness, and has to be taken off the planet for treatment aboard the Enterprise.
Kirk, Spock and McCoy collect her in the shuttlecraft Galileo. On the way back the craft is pulled off course by an energy being, the Companion, and set down on the planetoid Gamma Canaris N, where they find Zefram Cochrane alive and young.
Hedford, furious at the delay and afraid for her mission, grows steadily weaker. At the point of death she is joined with the Companion and chooses to stay with Cochrane. Kirk remarks that the Federation can find another negotiator for the planet.