So they couldnt fine any life forms on the planet, hence the reason the crew and the trador thought they were "ghosts". Yet it turns out there were two life forms on the planet, Was a reason given for this that I missed, or is it just lazy writing?
All I remember from this episode is Trip and the alien baking on the planet near the end. Enterprise has located them but decide there'a nothing they can do immediately to help. Yet nobody thought of, oh I don't know, beaming down a tent and air conditioner? Packs of ice, even? It was frustrating viewing.
I think they were in a shielded compartment at the time, so the scanners missed them along with their airponics bay. Wrong episode. That was "Dawn." "Oasis" was the first-season episode with Rene Auberjonois, the one that was basically a rehash of DS9's "Shadowplay" with the community of people who turned out to be holograms. Which I think was a mistake on the producers' part. Not only was it derivative, but the presence of sentient holographic artificial intelligences in the 22nd century is problematical. If the Kantare were able to achieve true AI sentience back then, and if Earth was in contact with them that early, then why was AI sentience so hard for people like Flint and Noonien Soong to achieve in later generations? I would've preferred it if the crew had turned out to be illusion-casting aliens of some kind, though that would've been too much like "Rogue Planet."