Stranger In Trouble is a backup mission, typically generated by a neighbor enclave member getting attacked while on the way to a scavenging location, or on the way home.
Get to the map marker. The character will be seen defending him/herself from multiple zombies. After the player helping the survivor kill all zombies in the area, the survivor will then say thanks and continue on his/her own. Occasionally, the player will be required to escort that survivor home.
Completing the mission improves attitude and trust of the rescued character.
If the mission expires, the character might get home safely, gets injured or, in rare instances, dies. If the character survives, their attitude and trust towards player will worsen.