Kidnapping

Kidnapping at (location) is a Minutemen radiant quest in Fallout 4. This quest can be started randomly when speaking to Preston Garvey or listening to Radio Freedom. If a settlement hasn't been unlocked yet, this quest may be started by speaking to a settler at that location and it will unlock the settlement. The kidnappers can be super-mutants, raiders or gunners.

Failure to free the kidnapped settler in a timely manner will result in the failure of the quest.

Detailed walkthrough
The ransom varies between 200 and 500 caps.