Twenty-year-old Sophie Marlowe has eighteen days until she takes control of the shares her late father left in trust. Her stepfather, former judge Vincent Hayes, has been siphoning money from it. To keep his hold, he takes her passport and phone, arranges a false psychiatric evaluation, and persuades her mother, Madeleine, that Sophie is unstable. Sophie secretly records the abuse and syncs the files to the cloud. When men arrive to take her to a care facility, she escapes onto the roof and falls onto a car. She survives, but Vincent isolates her in the ICU and hires an attacker to silence her. Sophie dies while Madeleine, misled by texts sent from Sophie's phone, remains unaware. When Madeleine learns the truth and realizes she delayed her daughter's rescue, she joins Sophie's friend Naomi and nurse Hannah. Pretending to remain Vincent's devoted wife, she helps gather recordings, blood test results, and trust records. Their evidence exposes Vincent at an estate hearing; he is arrested and sentenced to life in prison. Madeleine turns the mother-daughter distress signal, 'The streetlight's out,' into a hotline for people no one hears. Its first caller reveals that Vincent had accomplices.
