Growing up in Greenville, Texas, Bart Millard suffers physical and emotional abuse at the hands of his father, Arthur. When Arthur becomes terminally ill, he finds redemption by embracing his faith and rediscovering his love for his son. Years later, Bart's troubled childhood and mended relationship with his dad inspires him to write the hit song "I Can Only Imagine" as singer of the Christian band MercyMe.

After the breakout success of the song "I Can Only Imagine," MercyMe's Bart Millard is living the dream—sold-out arenas, a devoted fan base, and a thriving career. But behind the spotlight, Bart's past threatens the family he's built, especially the fragile bond with his son, Sam. When hopeful newcomer Tim Timmons joins the band for their biggest tour yet, he unknowingly brings a renewed gratitude to Bart's life through their unlikely friendship. Bart soon discovers that Tim carries hardships—and secrets—of his own, forcing him to face his past and repair his relationships with Sam and his wife, Shannon, before fame costs him what matters most.