It examines a set of American triplets, born in 1961 and adopted as six-month-old infants by separate families, unaware that each child had brothers. The separations were done as part of an undisclosed scientific "nature versus nurture" twin study, to track the development of genetically identical siblings raised in differing circumstances. Combining archival footage, re-enacted scenes, and present-day interviews, the documentary reveals how the brothers discovered one another at age 19 and thereafter sought to understand the circumstances of their separation.[3][4]