Your news, whenever it happens, wherever you are. NBC News NOW is streaming free, 24/7. | NBC News NOW

Watch NBC Nightly News with Lester Holt every Tuesday for our Snapshot – unique stories of talented and passionate Americans. | NBC Nightly News with Tom Llamas

"One pill could kill. One pill, one time, game over." Tonight on NBC Nightly News, Lester Holt talks to Cheri Oz, Special Agent in Charge of the DEA's Phoenix Field Division, about the fentanyl crisis. Watch the full report at 6:30 pm ET / 5:30 pm CT (check local listings). | NBC Nightly News with Tom Llamas