In 2264, Apohatsu led a small party that were to go undercover on the planet Mestiko following the Gelta nation's first warp flight, to evaluate the planet's natives, the Payav, for admission into the Federation. Over the next 18 months, Apohatsu and his team learned that Mestiko was going to be passed by a rogue pulsar which could lead to mass destruction on the planet.
Apohatsu made contact with Mino orDresha, the chief science advisor to Gelta's leadership, who was also becoming increasingly aware of the pulsar's threat. Apohatsu and Mino met several times to discuss the impending threat from the pulsar, though Apohatsu stressed that the Prime Directive limited his ability to help and would prevent them from helping. However, when First Consul Flen etHamwora learned of the presence of aliens on Mestiko, he asked for their help to save the planet.
Apohatsu then advocated Federation efforts to avert Mestiko's destruction. In late 2265, the USS Enterprise arrived with six probes designed by Professor Lindsey Cameron to deflect the pulsar's harmful x-ray radiation. Despite the risk that these experimental probes would not work successfully, Apohatsu and his team decided to remain on the planet's surface, and subsequently died. (TOS - Mere Anarchy eBook: Things Fall Apart)