41 is an independent feature-length documentary about Nicholas O'Neill, the youngest victim of the Station nightclub fire, which claimed the lives of 100 people in West Warwick, Rhode Island on February 20, 2003. The documentary, which was co-created by filmmakers Christian de Rezendes and Christian O'Neill (Nicholas's brother), interweaves the story of Nicholas's life, as described by his family, including his father, Dave Kane, and friends and illustrated with home videos, with footage from the film They Walk Among Us, which is based on a play of the same name written by Nicholas a year before he passed. The titular number, as described by the film, was of spiritual significance to Nicholas, although the reasons behind this are not fully known. The film also details how his family and friends believe that Nicholas may have prophetically known that he would die at a young age, and that he continues to communicate with them as a spirit, often through "signs" involving the number 41.

Several notable individuals either appear in the film or acted as consultants on it, including novelist Jon Land, writer Ann Hood, paranormal researcher Gary Schwartz, psychic mediums Robert Brown, Maureen Hancock and Cindy Gilman, and AVID co-creator Tom Ohanian. Both of the directors appear in the film and act as storytellers, relating their personal connection to the story.