NBC (10 p.m. ET)
The season premiere of Jack Klugman’s medical sleuth show is surely unique: While researching a story involving the chemical colchicine, writers Jeff Freilich and Christopher Trumbo learned that, although it is fatal in doses as small as 15 milligrams, it was being sold as a stimulant for marijuana plants. The discovery led the Environmental Protection Agency last month to ban the sale of colchicine.
FRIDAY, SEPTEMBER 21