Andrea sat frozen on the edge of the guest room bed, the glow of her phone screen the only light in the dark room. The message stared back at her, the letters sharp and impossible.

Unknown number: Hey… it’s Caleb. I’m back in Chicago for a while. I’ve been thinking about you a lot lately. Can we talk?

She blinked once. Twice. Then rubbed her eyes hard with the heels of her palms, as if the motion could wipe the words away like smudges on glass. When she opened her eyes again, the message was still there. Same words. Same number. Same ghost from her past reaching out at the...