Kym, portrayed by Anne Hathaway, is granted a temporary release from rehab to attend her sister Rachel's wedding in their Connecticut hometown. However, the moment she arrives, tension fills the air as Kym's family struggles to navigate the complexities of her troubled past and ongoing recovery. Her father, acutely concerned about her well-being, seems to be constantly monitoring her actions, which Kym interprets as a lack of trust.
Rachel, played by Rosemarie DeWitt, is preparing for her big day but feels overshadowed by Kym's presence and the attention her sister's past addiction attracts. The tension escalates at the rehearsal dinner, where Kym unexpectedly grabs the microphone to apologize for her past mistakes, as she seeks to make amends through her twelve-step program despite the discomfort it brings to her family.
At the heart of their strained relationship lies a deep-seated family tragedy. Kym carries the weight of guilt for the death of their younger brother, Ethan, who drowned while under Kym's care one fateful day when she was driving under the influence. This painful history looms over them, a specter neither Kym nor her family has fully confronted.
As the wedding day approaches, Kym inadvertently stirs more conflict when a past acquaintance from rehab approaches her, expressing gratitude for her story of resilience. This revelation ignites a fierce reaction from Rachel, who feels betrayed by Kym's fabrications and the focus it places back on her struggles. Their confrontation escalates later that night when Kym returns to their father's home, leading to an explosive argument where Rachel directly confronts Kym about the death of Ethan.
Desperate for understanding, Kym seeks solace from their mother, Abby, only to face more conflict. She confronts Abby about the day Ethan died, questioning why he was left in her care when she was using. Their conversation erupts into violence as accusatory words fly, amplifying Kym's sense of abandonment and lack of support. Overwhelmed, Kym takes a reckless drive, leading to a nighttime crash that leaves her with both physical and emotional scars.
On the morning of the wedding, Kym awakens to police presence after her ordeal and makes her way back to Rachel's room. The sight of Kym's bruised face softens Rachel’s heart, leading to a touching moment as she helps prepare her sister for the wedding. The ceremony celebrates love with a vibrant Indian theme, yet the reception leaves Kym feeling like an outsider, haunted by unresolved disagreements with their mother, who leaves early, leaving a gulf between Kym and her family unbridged.
As the festivities wind down and Kym's time away from rehab concludes, she faces the looming return to treatment. Yet, just before she departs, Rachel rushes out for a heartfelt goodbye, solidifying a promise to stay in touch. The journey toward healing continues for Kym, as she grapples with her past while finding hope in the bond with her sister.
