Kidnapped Trader

Kidnapped Trader (displayed as Kidnapped Trader at (Location Name)) is a Minutemen radiant quest in Fallout 4.

Detailed walkthrough
This quest can be periodically obtained when entering a settlement with a supply line to another settlement in place. The settlement leader will inform the Sole Survivor that one of their traders has been kidnapped for ransom by a group of raiders, super mutants, or Gunners.

There are two ways to proceed: the Sole Survivor can give the settlement leader enough caps to pay the ransom, completing the quest immediately, or they can offer to rescue the trader. If the kidnapped trader is not rescued or the ransom paid within 3 days of talking to the settlers, the trader will be killed and the quest will fail. Time is of the essence.

To rescue the kidnapped trader, the Sole Survivor must travel to the enemy hideout and locate them. They are often behind a locked door or gate deep in the hideout, and reaching them can prove quite dangerous. Killing the trader by accident will fail the quest, so the Sole Survivor should proceed with caution. After reaching the trader and talking to them, they will be freed and begin trying to return home. The quest can still fail if they die at this point, so the Sole Survivor may wish to escort them, especially if the area has not been fully cleared. After completing the rescue, the Sole Survivor can talk to the settlement leader to receive thanks and a reward of ~100 caps.

Bugs

 * If this quest appears in Sanctuary Hills and you accept it, the marker will only lead to a pack brahmin that cannot be interacted with.
 * In certain locations, NPCs might spawn in inaccessible locations (for instance, Roger Warwick at Warwick homestead might spawn inside the water cistern). This bug is shared with the other settlement quests.
 * This can be resolved by using the console command to teleport the NPC in question.
 * The Warwick homestead example can be resolved by building stairs into the cistern and a bell outside of it. Using the bell and waiting for an in-game hour (using the Wait option) will cause the NPCs to spawn near the bell.
 * Sometimes kidnapped NPCs might spawn without the quest being active, killing them and then talking to preston will activate the quest in the player's Pip Boy but it will remain unfinishable as the NPC is dead.