Through the Lens of Time

Junior medical officer Dana Gamble and Ortegas's documentarian brother Beto join an archaeological expedition led by Chapel and Korby, exploring an ancient building that Korby believes may hold the secret to immortality. When Gamble picks up a glowing orb, it explodes and destroys his eyes. He is transported back to the Enterprise while the rest of the away team, joined by Spock and La'An, are trapped in the building. M'Benga fails to restore Gamble's eyes and scans indicate that he is brain-dead, despite appearing to be conscious. The away team discovers that the building is a prison for the Vezda, extradimensional parasitic beings. They navigate the building's unusual metaphysical properties to escape. Batel, seemingly triggered by her Gorn DNA, recognizes Gamble as being possessed by a Vezda and attacks him. Gamble is apprehended by security and placed in the brig.

Summary from Wikipedia, CC BY-SA 4.0.