. >> reporter: for gabriela wilson, known widely as h.e.r., writing a song for "judas and the black messthe perfect thing. >> reporter: she drew inspiration from the work of fred hampton. the film is based on the life and dead of the fearless chicago-based activist. >> we watched the movie in the studio before we created this song. >> you can murder a revolutionary but you can't murder a revolution! you can't murder freedom! >> i thought about all the different storylines, and everybody was fighting for something. whether it was for themselves, for freedom, for for control, - everybody was fighting for something every single day. and the idea was to create this song that gave people hope. ♪ freedom going to keep us strong ♪ >> reporter: "fight for you" would become the film's final call to arms, a soulful cry for justice, revolution, revelation. ♪ fighting for my brothers fighting because they judge us ♪ >> freedom for each other, freedom from how they see us, freedom doesn't hang from the trees, things like that. >> freedom's not free. >> freedom is not free. >> you've said that everybo