When aging janitor Harlan Williams is accidentally exposed to exotic chemicals in a lab explosion, he undergoes an extraordinary change, which the government wants to study at any cost. Soon, Harlan, his wife Gina, and the lab's security chief are on a cross-country race to evade a murderously effective federal agent.

Set against the backdrop of the changing seasons has Paul, a short-fused ex-con who finds unlikely comfort, stability, and camaraderie when he takes an odd job in park maintenance. On his first day, he's teamed with Murph, a groundskeeping veteran who manages to defuse an outburst between Paul and their snide supervisor. Paul sticks with the job, and, as the months pass, he and Murph work their way through events both mundane and monumental, all the...