In this queer contemporary YA mystery, a nonbinary teen with autism realizes they must not only solve a 30-year-old mystery but also face the demons lurking in their past in order to live a satisfying life. Sam Sylvester has long collected stories of half-lived lives-of kids who died before they turned nineteen.

Sam was almost one of those kids. Now, as Sam's own nineteenth birthday approaches, their recent near-death experience haunts them. They're certain they don't have much time left.

Yet Sam's life seems to be on the upswing after meeting several new friends and a potential love interest in Shep, their next-door neighbour. Yet the past keeps roaring back-in Sam's memories and in the form of a thirty-year-old suspicious death that took place in Sam's new home. Sam can't resist trying to find out more about the kid who died and who now seems to guide their investigation.

When Sam starts receiving threatening notes, they know they're on the path to uncovering a murderer. But are they also approaching their own end? The Many Half-Lived Lives of Sam Sylvester explores healing in the aftermath of trauma and the joy in living a full life.