Set in a seedy Oklahoma City motel room, Bug centers on the meeting between Agnes, a divorced waitress with a fondness for cocaine and isolation, and Peter, a soft-spoken Gulf War drifter introduced to her by her lesbian friend, R.C. Agnes stays at a hotel in hopes of avoiding her physically abusive ex-husband, Jerry, who was just released from prison. At first, she lets Peter sleep platonically on her floor, but not long after she promotes him to the bed. Matters become more complicated as Jerry eagerly returns to the woman he loves to beat her up, expecting to resume their relationship. On top of that, there's a hidden bug infestation problem that has both Agnes and Peter dealing with scathing welts and festering sores-which has Peter believing this is the result of experiments conducted on him during his stay at an army hospital. Their fears soon escalate to paranoia, conspiracy theories and twisted psychological motives.