Common Side Effects

Marshall Cuso shows up in NYC with a mushroom, that can cure any disease or injury; his old classmate, Frances, meets him by chance, but keeps secret that she works for Reutical, a pharmaceutical company.

Marshall is on the run, trying to flee New York; Frances confides to her boss, Rick, about the mushroom; Rick sends her to Marshall's farm to get more, but the situation gets out of hand.

Marshall seeks advice from his old mentor Hildy; Copano and Harrington are drawn further into the mystery of the mushrooms obtained at the raid; Frances goes to Geneva with her boyfriend Nick and Rick but can't resist the call of the mushroom.

Marshall buys a plot of land near a chemical waste site with a plan to grow more mushrooms; Frances rushes home from Europe after a huge development; Copano and Harrington investigate a connection between Marshall and Frances.

Marshall, Frances, and their crazy neighbors deal with the aftermath of a dangerous incident.

Marshall arrives in jail and learns that some important people refuse to let him out, while danger lurks around every corner; Frances makes a fateful decision; Copano and Harrington pick up the pieces.