A young woman named Sarah is living a normal life until she starts receiving mysterious phone calls from an unknown caller. The caller seems to know everything about her and threatens to reveal her deepest secrets if she doesn't comply with his demands.
As Sarah tries to uncover the identity of the caller, she realizes that he is always one step ahead of her. She becomes paranoid and starts to question everyone around her, not knowing who she can trust.
Sarah soon finds herself caught in a web of lies and deceit, with no one to turn to for help. She must use all her wits and courage to outsmart the caller and put an end to his sinister game before it's too late.