TONIGHT: Lester Holt anchors NBC Nightly News live from Miami ahead of this week's Democratic debates. https://nbcnews.to/2xcVhSG Tune in at 6:30 ET / 5:30 CT on NBC (check your local listings). | NBC Nightly News with Tom Llamas

Coming up tonight: Brian Williams anchors NBC Nightly News live from Ferguson, Missouri. Here's a preview: | NBC Nightly News with Tom Llamas

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