Con un guión de Susannah Grant, basado en los artículos de Steve Lopez, ‘The Soloist’ se centra en la historia de Nathaniel Ayers, un músico vagabundo de Los Angeles, enfermo de esquizofrenia, cuyo sueño es poder tocar en el Walt Disney Concert Hall. Este personaje (real) es encarnado en la gran pantalla por Foxx, mientras que Downey Jr. se ocupa de interpretar a Lopez, el periodista que le descubre y comienza a escribir sobre él. Catherine Keener, Stephen Root, Tom Hollander, Angela Featherstone, Rachael Harris y Lisa Gay Hamilton completan el reparto.

In 2005, the only thing hurting Los Angeles Times columnist Steve Lopez more than his face from a recent bike accident was his pressing need for story ideas. That is when he discovers Nathaniel Ayers, a mentally ill, homeless street musician who possesses extraordinary talent, even through his half-broken instruments. Inspired by his story, Lopez writes an acclaimed series of articles about Ayers and attempts to do more to help both him and the rest of the underclass of LA have a better life. However, Lopez's good intentions run headlong in the hard realities of the strength of Ayers' personal demons and the larger social injustices facing the homeless. Regardless, Lopez and Ayers must find a way to conquer their deepest anxieties and frustrations to hope for a brighter future for both of them.