The Effect is set during a clinical trial where paid volunteers test new pharmaceutical drugs in hopes of finding a cure for depression. Under the supervision of Dr. Lorna James, two patients, Connie and Tristan, are tested in more ways than one. Their attraction to each other becomes increasingly passionate and out of control as the dosage of the drug gets higher. The question is whether the growing intensity between the two is a side effect of the drug or real. Throughout the trial, opposing views within the medical profession are presented through Dr. James, the physician in charge, and the Pharma company doctor Toby Sealey. The sudden and illicit romance between Connie and Tristan forces the supervising doctors to face off over the ethical consequences of their work.