Evan Taft has plans. Take a gap year in Alaska, make sure his brother and single mother are taken care of, and continue therapy to process his father's departure. But after his mum's unexpected cancer diagnosis, and as Evan's plans begin to fade, he hears something - a song no one else can hear, the voice of a mysterious singer ...

Shosh Bell has dreams. A high-school theatre legend, she's headed to performing arts college in LA, a star on the rise. But when a drunk driver takes her sister's life, that star fades to black. All that remains is a void - and a soft voice singing in her ear ...

Over it all, transcending time and space, a celestial bird brings strangers together: from an escaped murderer in 19th-century Paris, to a Norwegian cosmonaut in low-earth orbit, something is happening that began long ago, and will long outlast Evan and Shosh.