ZAAD tells the autobiographical story of Dries Meddens. After the death of his mother, the care for Dries' bipolar father falls on his plate. He discovers how crudely and ruthlessly society and psychiatry treat patients. His father eventually dies in solitary confinement. While emptying his parent’s home, Dries discovers an old letter from his grandfather. The man appears to have led a busy, productive life. He is the founder of an internationally renowned seed breeding company and still has time to paint, write diaries and conduct intensive correspondence. Dries finds similarities between his grandfather, his father and himself. Slowly the fear grows that his father's psychiatric illness might be hereditary. Strolling through the family’s film and photo archives, with dramatic and sometimes hilarious finds, Dries tries to find answers. He also consults a psychiatrist. Together the consultations and reviewing of his archival material help Dries look at bipolarity with new eyes.