Captain Kirk and several crew members beam down to the surface of a previously-unknown planet. They immediately discover that their communicators and phasers no longer work, and they cannot get back to the Enterprise until they manage to locate the main power source on the planet, and knock it out. Fortunately, they always manage to beam down within 50 feet of "the main power source". It's never a case where they, for example, beamed down in Japan, and the main power source is over in Belgium somewhere.
(And as we all know, if a non-regular is part of the landing party, that guy's toast 5 minutes after his arrival on the planet!)
.......and the one you never saw before is gonna die.