Set in the 1930s, the film portrays O'Sullivan and his son setting off across Depression-era America in search of the killer of several members of their family. National figures show amyotrophic lateral sclerosis, or ALS, affects one out of 50,000 people, most in middle age. But 11 people within five miles of each other near Greenville have ALS or died of it in the past six years. With about 20,000 residents in Greenville and the lake-studded townships near the border of Kent and Montcalm counties, that puts the occurrence of ALS at nearly 30 times the average. Today 30,000 Americans live with ALS, which destroys neurons that control movement.
Patients gradually lose their ability to move, to swallow, and finally, to breathe.
A similar group of ALS cases has turned up in Cadillac. Ten people who live within a few miles of each other, in the town of 10,000, have come down with the disease since 1993. That's about 50 times the average. Doctors want to know whether the clusters are a coincidence. Despite the lack of a proven cause for ALS, some Cadillac residents cannot help but wonder about the town's industrial park, which was declared a federal Superfund cleanup site in 1981.