Since retiring from the NBA, Chris Herren has visited schools across the country, urging students not to make the same mistakes he did. 

Throughout his college and NBA career, Herren battled substance abuse issues, culminating in a heroin overdose in 2008. Paramedics said he had died for 30 seconds. Herren recounted that instance and several other stunning encounters with drugs in his memoir, "Basketball Junkie and in "Unguarded," an ESPN 30 for 30 documentary directed by Jonathan Hock. 

On Tuesday, we'll get a new look at Herren's story, this time focused on his mission to educate young people on the realities of addiction. Watch the cathartic trailer for "The First Day" here: 

Herren played two seasons in the NBA, one of which came with the Celtics. Tuesday's documentary airs on ESPN at 8 p.m. ET. Like "Unguarded," "The First Day" is also directed by Jonathan Hock. 

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