In 1967, Harvard Medical School professor Dr. Lester Grinspoon set out to research marijuana sufficiently to convince his best friend—famed astronomer Carl Sagan—to stop smoking weed all the time. But after making a fateful trip to the library, Grinspoon returned convinced the case against Mary Jane was all lies and propaganda. So Lester and Carl began enthusiastically exploring the cannabis "Cosmos" together, igniting the medical cannabis movement and sparking many stoned epiphanies along the way.