So you've been Sleeped, Webbed or otherwise incapacitated by your enemies. Will they now cut your throat in cold blood? Possibly, that's what you'd do to them. But if not:
1. Your captors take all your items, even your clothes. Then they set you free.
2. Your captors decide, whether rationally or otherwise, that they can get a good price by holding you for ransom. You are locked/tied up somewhere while a series of opaque Coen Brother-style negotiations go on in the next room.
3. Your captors are slave traders. They strip you of your belongings, attach collars to your necks and take you to the nearest market.
4. Your captors are a slave-driving race who regard all other humans as inferior. They take you as their slaves directly and put you to work on a construction project or perhaps in support of their armies.
5. Your captors are cultists. They take you to their temple to be sacrificed to their dark god.
6. Your captors are cultists. They regard you as avatars of their dark gods. They take you to their temple where your every wish is catered to, except your wish to escape. Also, they seem to be marking off the days since your arrival on a stone calendar...
7. Your captors serve a powerful wizard. You are taken to his laboratory to be polymorphed or grafted in his bizarre experiments. If you survive the experiments you may actually be better off than you were before.
8. Your captors are fairies. You serve a mysterious durance in their fairy kingdom. You age 50 years but the world remains unchanged, or maybe vice versa.
9. Your captors are cannibals, or possibly just another race that likes to eat humans. They lock you in a pen and prepare to cook the burliest of your party (anyone with STR or CON above 13). The others they will fatten up for several weeks before devouring.
10. Your captors are a brutal race who respect strength above all else.
They take you in chains to a gladiatorial arena where you may fight wild
animals for a chance at freedom or even knighthood in their savage
11. Your captors are the worst monsters of all - adventurers! They steal your gear, then take you as 'hirelings' who will be expected to walk first into every dangerous situation.
12. Your captors are organ thieves. They steal the choicest organ from each of your bodies, depending on your highest stat (STR = arm, DEX = leg, CON = kidney, liver, lung or heart, INT = brain, WIS = eyes, CHA = face). They will then bind and treat your wounds carefully. "We're not murderers, you know!"