The 3 security officers are promply killed by the natives, and the rest of the landing party is captured. Meanwhile, back in orbit, Scotty notices a Klingon ship approaching and must warp out of orbit to escape detection. Bones cures the native king who is suffering from the flu, and as a reward the landing party is set free and given all of the light bulbs they can carry. Scotty cripples the Klingon ship and warps back to the planet just in time to beam up Kirk et. The new bulb is inserted, and the Enterprise continues with its five year mission.
Efficiency experts replace only dark bulbs.
One to give the bulb to the screw-inner. One to screw in the bulb. One to hold him on the stepladder. Four to hold the stepladder steady. One to flick the switch to test the bulb.