Necklace

Here's a sad symbol for y'all. (Hey, it's a book about the apocalypse. What did you expect?)

Ben had a baby sister around Sammy's age. Notice the past tense.

When looters murdered his family, Ben's sister was pulled from his protective arms. He tried to reach for her, but all he got was the necklace:

My fingers hook on to the locket around her neck and tear the silver chain free. (12.35)

This necklace becomes sort of a lifeline for Ben; it's extremely important to him. When he loses it in the hospital, he loses his will to live. He says,

Somewhere between the basement room and this room, I lost Sissy's locket. I wake up in the middle of the night, my hand clutching empty air, and I hear her screaming my name like she's standing two feet away… (30.13)

He becomes so depressed he stops eating. It's like his sister dies all over again.

One day, Colonel Vosch brings the necklace back to Ben. Coincidence? We think not.

From that moment, Ben decides he's going to live. Over time, he befriends Sammy, a kid who's thrust into his squad. (Sammy's five—the same age as Ben's dead sister.) When Ben is called away from the base, he leaves the necklace with Sammy as a token of his promise to return:

I reach into my pocket and pull out Sissy's locket. Undo the clasp. I haven't done that since I fixed it at Tent City. Circle Broken. I draw it around his neck and hook the ends together. Circle complete. (51.15)

Ben's promise is binding, and he does return for Sammy, at great personal cost. In doing so, he helps put to rest the ghost of his little sister, the one he couldn't save.