Session Aces. Keepers of Time. Vocalists. Composers. The sidemen and sidewomen who play the riffs and fills we imitate in the air. When we turn up the radio, chances are we are listening to one of these players. A-listers have them on speed dial. International tour or recording session, who’re they gonna call? A “Hired Gun.” This feature length one-off documentary introduces the prolific musicians who are virtually unknown to the public. Billy Joel, Whitesnake, P!NK and Metallica are synonymous with their own artistry and success, but who is responsible for their instrumental solos? Who tours with them live? It is the consummate side players who kill it show after show, often playing circles around the actual band members. In “Hired Gun,” viewers learn the firsthand stories from individuals who have mastered their craft and perform on the world’s biggest stages. This film details the highs and lows of touring life, the demands of hectic session schedules, and the dedication required to make dreams a reality. The unsung stories of these heroes are now brought to the screen. “Hired Gun” explores the creative process and sound of the best permanently on-call musicians in the world. Some have been constantly undervalued and face the wreckage of a failed career. Some remain in demand, happy to be playing, singing, and songwriting in relative obscurity and supporting the star. Some step into the spotlight and become leaders in their own band.