The film unfolds across two distinct eras, the 1960s and the late 1980s, weaving between these time periods to tell the story of musical genius and personal turmoil.
In the 1960s, we witness legendary moments in music history as The Beach Boys are seen recording in the studio. During a party, Brian Wilson expresses to his brothers that he prefers to stay home and focus on songwriting rather than go on tour this time. They agree, believing in his creative vision. Brian shares an early version of "God Only Knows" with his father, their former manager, seeking honesty regarding its quality, only to be dismissed with criticism that leaves him unsettled.
As Brian delves deeper into his craft, he collaborates with other musicians on tracks like "Wouldn't It Be Nice" and "God Only Knows," receiving accolades for his undeniable talent. However, tensions arise when his cousin Mike Love begins to voice dissatisfaction, feeling that the creativity is overshadowed by Brian's dominant role. The band members, heavily influenced by drugs and particularly LSD, spiral into chaos as Brian starts to experience unsettling auditory hallucinations. His mental state deteriorates, manifesting in a confusing blend of creativity and disarray. Following an intense drug session, he plays "Good Vibrations" for Mike, but the pressure mounts as Brian suffers a breakdown at a dinner party, succumbing to the overwhelming sounds around him.
In a shocking turn, Brian’s father reveals that he has sold the rights to their music for a mere $750,000. As Brian grapples with his mental health, he retreats from the world, ultimately spending three years confined to his home, as detailed later in his conversation with Melinda.
Transitioning to the 1980s, we see an older Brian, now portrayed by John Cusack, at a Cadillac dealership where he meets Melinda Ledbetter, a car saleswoman who finds his peculiar behavior intriguing yet concerning. Brian, in a bid to reclaim control over his life, leaves her a note disclosing his feelings of loneliness and fear. Their relationship begins as he awkwardly asks her out on a date, though he is constantly accompanied by Dr. Eugene "Gene" Landy, played by Paul Giamatti, who is not only his doctor but also his guardian.
Their dates reveal deeper layers of Brian's troubled past, as he recounts the abuse he suffered, reducing him to a state of vulnerability. Scenes of his medication regimen showcase the difficult balance between care and control, particularly when Gene interjects during their moments together. Despite this, an intimate encounter unfolds at his beach house, only to be disrupted by Brian's mounting paranoia.
As their relationship develops, Melinda discovers the extent of Gene's overreach, culminating in a visit to Brian where she uncovers a massive jar filled with pills, stashed away by the housekeeper, Gloria. Melinda's concern grows, along with her determination to help Brian escape Gene's oppressive grip. Throughout their tumultuous journey, she navigates legalities and family connections, seeking a way to reunite Brian with his loved ones and liberate him from Gene's tyrannical control.
Things come to a head when Melinda nearly collides with Brian as he wanders aimlessly in the street. Their ensuing conversation brings him a sense of clarity, leading him to express a desire to leave his troubled past behind and pursue a future with her. Eventually, the truth emerges: Gene loses his medical license and Brian finally receives the appropriate treatment he desperately needs.
The film culminates in a celebration of their love, as Brian and Melinda marry in 1995 and joyfully expand their family with five children, a testament to the resilience of love in the face of adversity. Through highs and lows, the narrative underlines the profound impact of compassion, connection, and the journey of healing.
