There’s something destroying civilisations, spreading some kind of mass insanity and the crew of the Enterprise have their best investigating hats on to find out what. Luckily the spread of crazy flu has moved from planet to planet in a straight line making the task of anticipating where the disease is going next easier.
On their way they spot a spaceship heading into the sun. However, despite Uhura’s best efforts they cannot communicate with it and despite Scotty’s best efforts they can’t tractor beam it. What do they pay these guys for?! The matter resolves itself when they hear a voice on the radio saying “I’m finally free!” before the ship plummets into the Sun. I know how he feels. I’ve had mobile phone contracts that have left me feeling like that.