It's the middle of the apocalypse and Person A, Person B and a few others are hiding out and fighting zombies as survivors. A's family has disappeared, presumably dead and/or infected. This causes A to mostly isolate themselves. Soon enough, A starts to find everything they're doing pointless and thinks they should just give up. B tells A that's not what their family would want, to which A responds, "Well, they're not here, are they?!" And storms away. Eventually, B finds A and comforts them, bringing them back to base.
!!Bonus if you don't want everything to be depressing!!
While fighting at one point, the group finds (a) member(s) of A's family.
