Marty McFly's red guitar from the original "Back to the Future" is missing and the movie's cast and filmmakers are asking for the public's help.

Marty McFly grabbed a guitar in “Back to the Future” and rocked out with the band at a 1950s high school dance, helping him narrowly avoid blinking out of existence before time-traveling back to the 1980s.

A new documentary sheds light on the search for Marty McFly's red guitar from Back to the Future, which has been missing for 40 years.