The planet to which the Enterprise is carrying urgently needed medical supplies for the plague-stricken New Paris colonies when the shuttlecraft Galileo is lost in The Galileo Seven.
Makus III is the destination of the Enterprise in the Original Series episode The Galileo Seven. The ship is carrying medical supplies that must be handed over there for onward transport to the New Paris colonies, where a plague is out of control.
On the way the ship passes the quasar-like formation Murasaki 312, which Kirk has standing orders to investigate. The shuttlecraft Galileo, commanded by Spock, is pulled off course and crashes on Taurus II.
The appointment at Makus III becomes the clock of the story. Galactic High Commissioner Ferris, travelling aboard to supervise the transfer, insists that the search end in time to make the rendezvous, and he finally takes authority to order the ship away, although Kirk leaves at the slowest speed he dares.